{"transactions":[{"id":682533,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2026-08-19T00:02:54.000Z","date":"2026-08-15","kind":"tax_withholding","planned":true,"acquired":false,"shares":28950,"price":18.49,"value":535285.5,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F3","text":"Represents shares of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\") withheld by the Issuer to satisfy tax withholding obligations in connection with the vesting and settlement of restricted stock units (\"RSUs\")."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F4","text":"Consists of (i) 89,917 shares of Series A Common Stock; (ii) 478,053 unvested RSUs awarded under the Issuer's 2023 Stock Option and Incentive Plan (the \"Plan\"), each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement; and (iii) 227,272 unvested performance stock units awarded under the Plan, each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement."}],"balance_after":795242,"source":{"system":"sec-edgar","filing":"0001470831-26-000839","document":"wk-form4_1787097772.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083126000839/wk-form4_1787097772.xml","form_type":"4"}},{"id":682532,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2026-08-19T00:02:54.000Z","date":"2026-08-14","kind":"sale","planned":true,"acquired":false,"shares":14000,"price":18.47,"value":258580.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 21, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $18.25 to $18.82 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":824192,"source":{"system":"sec-edgar","filing":"0001470831-26-000839","document":"wk-form4_1787097772.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083126000839/wk-form4_1787097772.xml","form_type":"4"}},{"id":702857,"issuer":{"id":28500,"kind":"organization","name":"Taylor Morrison Home Corp","symbol":"TMHC"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Deferred Stock Units","published_at":"2026-07-27T20:15:25.000Z","date":"2026-07-24","kind":"disposition_to_issuer","planned":false,"acquired":false,"shares":3287,"price":72.5,"value":238307.5,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F1","text":"Each deferred stock unit (\"DSU\") represents a contingent right to receive one share of common stock, par value $0.00001 per share, of Taylor Morrison Home Corporation (the \"Issuer\"). On July 24, 2026, Berkshire Hathaway Inc. (\"BHI\") acquired the Issuer pursuant to an Agreement and Plan of Merger, dated as of May 31, 2026 (the \"Merger Agreement\"), by and among the Issuer, BHI and WXYZ Merger Sub, Inc., a wholly owned subsidiary of BHI (\"Merger Sub\"). In accordance with the Merger Agreement, Merger Sub merged with and into the Issuer (the \"Merger\") with the Issuer surviving the Merger as a wholly owned subsidiary of BHI. At the effective time of the Merger, each outstanding DSU became immediately vested, was cancelled and converted into the right to receive an amount in cash equal to (x) the number of shares subject to such DSU as of immediately prior to the Effective Time, multiplied by (y) $72.50."},{"field":"kind","element":"transactionCoding","label":"F1","text":"Each deferred stock unit (\"DSU\") represents a contingent right to receive one share of common stock, par value $0.00001 per share, of Taylor Morrison Home Corporation (the \"Issuer\"). On July 24, 2026, Berkshire Hathaway Inc. (\"BHI\") acquired the Issuer pursuant to an Agreement and Plan of Merger, dated as of May 31, 2026 (the \"Merger Agreement\"), by and among the Issuer, BHI and WXYZ Merger Sub, Inc., a wholly owned subsidiary of BHI (\"Merger Sub\"). In accordance with the Merger Agreement, Merger Sub merged with and into the Issuer (the \"Merger\") with the Issuer surviving the Merger as a wholly owned subsidiary of BHI. At the effective time of the Merger, each outstanding DSU became immediately vested, was cancelled and converted into the right to receive an amount in cash equal to (x) the number of shares subject to such DSU as of immediately prior to the Effective Time, multiplied by (y) $72.50."},{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Each deferred stock unit (\"DSU\") represents a contingent right to receive one share of common stock, par value $0.00001 per share, of Taylor Morrison Home Corporation (the \"Issuer\"). On July 24, 2026, Berkshire Hathaway Inc. (\"BHI\") acquired the Issuer pursuant to an Agreement and Plan of Merger, dated as of May 31, 2026 (the \"Merger Agreement\"), by and among the Issuer, BHI and WXYZ Merger Sub, Inc., a wholly owned subsidiary of BHI (\"Merger Sub\"). In accordance with the Merger Agreement, Merger Sub merged with and into the Issuer (the \"Merger\") with the Issuer surviving the Merger as a wholly owned subsidiary of BHI. At the effective time of the Merger, each outstanding DSU became immediately vested, was cancelled and converted into the right to receive an amount in cash equal to (x) the number of shares subject to such DSU as of immediately prior to the Effective Time, multiplied by (y) $72.50."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F1","text":"Each deferred stock unit (\"DSU\") represents a contingent right to receive one share of common stock, par value $0.00001 per share, of Taylor Morrison Home Corporation (the \"Issuer\"). On July 24, 2026, Berkshire Hathaway Inc. (\"BHI\") acquired the Issuer pursuant to an Agreement and Plan of Merger, dated as of May 31, 2026 (the \"Merger Agreement\"), by and among the Issuer, BHI and WXYZ Merger Sub, Inc., a wholly owned subsidiary of BHI (\"Merger Sub\"). In accordance with the Merger Agreement, Merger Sub merged with and into the Issuer (the \"Merger\") with the Issuer surviving the Merger as a wholly owned subsidiary of BHI. At the effective time of the Merger, each outstanding DSU became immediately vested, was cancelled and converted into the right to receive an amount in cash equal to (x) the number of shares subject to such DSU as of immediately prior to the Effective Time, multiplied by (y) $72.50."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F1","text":"Each deferred stock unit (\"DSU\") represents a contingent right to receive one share of common stock, par value $0.00001 per share, of Taylor Morrison Home Corporation (the \"Issuer\"). On July 24, 2026, Berkshire Hathaway Inc. (\"BHI\") acquired the Issuer pursuant to an Agreement and Plan of Merger, dated as of May 31, 2026 (the \"Merger Agreement\"), by and among the Issuer, BHI and WXYZ Merger Sub, Inc., a wholly owned subsidiary of BHI (\"Merger Sub\"). In accordance with the Merger Agreement, Merger Sub merged with and into the Issuer (the \"Merger\") with the Issuer surviving the Merger as a wholly owned subsidiary of BHI. At the effective time of the Merger, each outstanding DSU became immediately vested, was cancelled and converted into the right to receive an amount in cash equal to (x) the number of shares subject to such DSU as of immediately prior to the Effective Time, multiplied by (y) $72.50."}],"balance_after":0,"derivative":{"underlying":"Common Stock","underlying_shares":3287},"source":{"system":"sec-edgar","filing":"0001193125-26-318111","document":"ownership.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1562476/000119312526318111/ownership.xml","form_type":"4"}},{"id":706283,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2026-07-18T00:01:17.000Z","date":"2026-07-16","kind":"sale","planned":true,"acquired":false,"shares":14000,"price":17.75,"value":248500.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 21, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $17.43 to $18.05 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F3","text":"Consists of (i) 59,302 shares of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"); (ii) 551,618 unvested restricted stock units awarded under the Issuer's 2023 Stock Option and Incentive Plan (the \"Plan\"), each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement; and (iii) 227,272 unvested performance stock units awarded under the Plan, each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement."}],"balance_after":838192,"source":{"system":"sec-edgar","filing":"0001470831-26-000720","document":"wk-form4_1784332874.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083126000720/wk-form4_1784332874.xml","form_type":"4"}},{"id":731527,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2026-06-19T00:08:45.000Z","date":"2026-06-18","kind":"sale","planned":true,"acquired":false,"shares":14000,"price":13.23,"value":185220.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 21, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $13.12 to $13.49 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F3","text":"Consists of (i) 73,302 shares of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"); (ii) 551,618 unvested restricted stock units awarded under the Issuer's 2023 Stock Option and Incentive Plan (the \"Plan\"), each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement; and (iii) 227,272 unvested performance stock units awarded under the Plan, each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement."}],"balance_after":852192,"source":{"system":"sec-edgar","filing":"0001470831-26-000561","document":"wk-form4_1781827722.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083126000561/wk-form4_1781827722.xml","form_type":"4"}},{"id":763266,"issuer":{"id":28500,"kind":"organization","name":"Taylor Morrison Home Corp","symbol":"TMHC"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Deferred Stock Units","published_at":"2026-05-26T22:10:35.000Z","date":"2026-05-21","kind":"grant","planned":false,"acquired":true,"shares":3287,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F1","text":"Each deferred stock unit represents a contingent right to receive one share of Common Stock. The deferred stock units shall be vested upon the earlier of (i) the first anniversary of the date of grant and (ii) the date of the Company's annual meeting of stockholders immediately following the date of grant. The deferred stock units will be settled in shares of Common Stock upon the earlier of (i) the reporting person's separation from service on the Company's board of directors or (ii) a change in control."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The deferred stock units were acquired by Ms. Whalen pursuant to the terms of the Company's Non-Employee Director Deferred Compensation Plan, under which directors may elect to defer their annual equity award granted pursuant to the Taylor Morrison 2013 Omnibus Equity Award Plan, as amended."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F1","text":"Each deferred stock unit represents a contingent right to receive one share of Common Stock. The deferred stock units shall be vested upon the earlier of (i) the first anniversary of the date of grant and (ii) the date of the Company's annual meeting of stockholders immediately following the date of grant. The deferred stock units will be settled in shares of Common Stock upon the earlier of (i) the reporting person's separation from service on the Company's board of directors or (ii) a change in control."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F1","text":"Each deferred stock unit represents a contingent right to receive one share of Common Stock. The deferred stock units shall be vested upon the earlier of (i) the first anniversary of the date of grant and (ii) the date of the Company's annual meeting of stockholders immediately following the date of grant. The deferred stock units will be settled in shares of Common Stock upon the earlier of (i) the reporting person's separation from service on the Company's board of directors or (ii) a change in control."}],"balance_after":3287,"derivative":{"underlying":"Common Stock","underlying_shares":3287},"source":{"system":"sec-edgar","filing":"0001193125-26-239816","document":"ownership.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1562476/000119312526239816/ownership.xml","form_type":"4"}},{"id":774231,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series B Common Stock","published_at":"2026-05-19T00:08:41.000Z","date":"2026-05-15","kind":"exercise","planned":true,"acquired":false,"shares":13527,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"kind","element":"transactionCoding","label":"F4","text":"Represents 13,527 shares of Series B Common Stock automatically converted into shares of Series A Common Stock in connection with tax withholding obligations related to the vesting and settlement of restricted stock units (\"RSUs\")."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F7","text":"Consists of 269,585 shares of Series B Common Stock."}],"balance_after":269585,"derivative":{"underlying":"Series A Common Stock","underlying_shares":13527},"source":{"system":"sec-edgar","filing":"0001470831-26-000455","document":"wk-form4_1779149319.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":6,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083126000455/wk-form4_1779149319.xml","form_type":"4"}},{"id":774230,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series B Common Stock","published_at":"2026-05-19T00:08:41.000Z","date":"2026-05-14","kind":"exercise","planned":true,"acquired":false,"shares":14000,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 21, 2025."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."}],"balance_after":283112,"derivative":{"underlying":"Series A Common Stock","underlying_shares":14000},"source":{"system":"sec-edgar","filing":"0001470831-26-000455","document":"wk-form4_1779149319.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":5,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083126000455/wk-form4_1779149319.xml","form_type":"4"}},{"id":774229,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2026-05-19T00:08:41.000Z","date":"2026-05-15","kind":"tax_withholding","planned":true,"acquired":false,"shares":42476,"price":14.38,"value":610804.88,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F5","text":"Represents shares of Series A Common Stock withheld by the Issuer to satisfy tax withholding obligations in connection with the vesting and settlement of RSUs."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F6","text":"Consists of (i) 87,302 shares of Series A Common Stock; (ii) 551,618 unvested RSUs awarded under the Issuer's 2023 Stock Option and Incentive Plan (the \"Plan\"), each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement; and (iii) 227,272 unvested performance stock units awarded under the Plan, each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement."}],"balance_after":866192,"source":{"system":"sec-edgar","filing":"0001470831-26-000455","document":"wk-form4_1779149319.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083126000455/wk-form4_1779149319.xml","form_type":"4"}},{"id":774228,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2026-05-19T00:08:41.000Z","date":"2026-05-15","kind":"exercise","planned":true,"acquired":true,"shares":13527,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F4","text":"Represents 13,527 shares of Series B Common Stock automatically converted into shares of Series A Common Stock in connection with tax withholding obligations related to the vesting and settlement of restricted stock units (\"RSUs\")."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."}],"balance_after":908668,"source":{"system":"sec-edgar","filing":"0001470831-26-000455","document":"wk-form4_1779149319.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083126000455/wk-form4_1779149319.xml","form_type":"4"}},{"id":774227,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2026-05-19T00:08:41.000Z","date":"2026-05-14","kind":"sale","planned":true,"acquired":false,"shares":14000,"price":14.26,"value":199640.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 21, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F3","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $13.88 to $14.45 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":895141,"source":{"system":"sec-edgar","filing":"0001470831-26-000455","document":"wk-form4_1779149319.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083126000455/wk-form4_1779149319.xml","form_type":"4"}},{"id":774226,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2026-05-19T00:08:41.000Z","date":"2026-05-14","kind":"exercise","planned":true,"acquired":true,"shares":14000,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 21, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."}],"balance_after":909141,"source":{"system":"sec-edgar","filing":"0001470831-26-000455","document":"wk-form4_1779149319.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083126000455/wk-form4_1779149319.xml","form_type":"4"}},{"id":805000,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series B Common Stock","published_at":"2026-04-18T00:10:58.000Z","date":"2026-04-16","kind":"exercise","planned":true,"acquired":false,"shares":4293,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F5","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of Series A Common Stock, and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"kind","element":"transactionCoding","label":"F4","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 21, 2025."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F5","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of Series A Common Stock, and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F5","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of Series A Common Stock, and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F8","text":"Consists of (i) 262,737 shares of Series B Common Stock and (ii) 34,375 unvested RSUs awarded under the Issuer's 2015 Stock Incentive Plan, each representing the contingent right to receive one share of Series B Common Stock upon vesting and settlement."}],"balance_after":297112,"derivative":{"underlying":"Series A Common Stock","underlying_shares":4293},"source":{"system":"sec-edgar","filing":"0001470831-26-000380","document":"wk-form4_1776471055.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":5,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083126000380/wk-form4_1776471055.xml","form_type":"4"}},{"id":804999,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2026-04-18T00:10:58.000Z","date":"2026-04-16","kind":"sale","planned":true,"acquired":false,"shares":14000,"price":18.54,"value":259560.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F4","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 21, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F6","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $18.34 to $18.98 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F7","text":"Consists of (i) 42,687 shares of Series A Common Stock; (ii) 625,182 unvested RSUs awarded under the Plan, each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement; and (iii) 227,272 unvested PSUs awarded under the Plan, each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement."}],"balance_after":895141,"source":{"system":"sec-edgar","filing":"0001470831-26-000380","document":"wk-form4_1776471055.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083126000380/wk-form4_1776471055.xml","form_type":"4"}},{"id":804998,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2026-04-18T00:10:58.000Z","date":"2026-04-16","kind":"exercise","planned":true,"acquired":true,"shares":4293,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F4","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 21, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F5","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of Series A Common Stock, and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."}],"balance_after":909141,"source":{"system":"sec-edgar","filing":"0001470831-26-000380","document":"wk-form4_1776471055.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083126000380/wk-form4_1776471055.xml","form_type":"4"}},{"id":804997,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2026-04-18T00:10:58.000Z","date":"2026-04-15","kind":"grant","planned":true,"acquired":true,"shares":227272,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F2","text":"Represents performance stock units (\"PSUs\") awarded under the Plan, each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement. The PSUs will vest in up to three tranches over a two-year measurement period, subject to the achievement of specified performance targets tied to the trading price of the Series A Common Stock and the Reporting Person's continued service in the same or substantially equivalent position as the Reporting Person held as of the grant date through the applicable vesting date. Each tranche of PSUs will vest only if the average closing price of the Series A Common Stock for a period of at least sixty consecutive calendar days is at or above a specified dollar value during the applicable measurement period."},{"field":"shares","element":"transactionShares","label":"F3","text":"(continued) The stock price targets for tranches 1 through 3 are $30.00, $50.00, and $75.00 per share, respectively, subject to proportionate adjustment in the event of any stock split or other similar change in the Issuer's capital stock."}],"balance_after":904848,"source":{"system":"sec-edgar","filing":"0001470831-26-000380","document":"wk-form4_1776471055.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083126000380/wk-form4_1776471055.xml","form_type":"4"}},{"id":804996,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2026-04-18T00:10:58.000Z","date":"2026-04-15","kind":"grant","planned":true,"acquired":true,"shares":265151,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"Represents restricted stock units (\"RSUs\") awarded under the Issuer's 2023 Stock Option and Incentive Plan (the \"Plan\"), each representing the contingent right to receive one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), upon vesting and settlement. The RSUs vest as follows: (i) 50% of the RSUs will vest in eight equal quarterly installments, with the first such installment vesting on May 15, 2026, and (ii) thereafter the remaining 50% of the RSUs will vest in four equal quarterly installments, subject to the Reporting Person's continued service on each such vesting date."}],"balance_after":677576,"source":{"system":"sec-edgar","filing":"0001470831-26-000380","document":"wk-form4_1776471055.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083126000380/wk-form4_1776471055.xml","form_type":"4"}},{"id":843401,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2026-03-13T23:57:52.000Z","date":"2026-03-12","kind":"sale","planned":true,"acquired":false,"shares":5077,"price":19.34,"value":98189.18,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 21, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F3","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $19.27 to $19.38 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F4","text":"Consists of (i) 52,394 shares of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and (ii) 360,031 unvested restricted stock units awarded under the Issuer's 2023 Stock Option and Incentive Plan, each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement."}],"balance_after":412425,"source":{"system":"sec-edgar","filing":"0001470831-26-000270","document":"wk-form4_1773446269.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083126000270/wk-form4_1773446269.xml","form_type":"4"}},{"id":843400,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2026-03-13T23:57:52.000Z","date":"2026-03-12","kind":"sale","planned":true,"acquired":false,"shares":8923,"price":19.72,"value":175961.56,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 21, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $19.385 to $20.38 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":417502,"source":{"system":"sec-edgar","filing":"0001470831-26-000270","document":"wk-form4_1773446269.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083126000270/wk-form4_1773446269.xml","form_type":"4"}},{"id":895526,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series B Common Stock","published_at":"2026-02-18T21:12:33.000Z","date":"2026-02-15","kind":"exercise","planned":true,"acquired":false,"shares":29513,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"kind","element":"transactionCoding","label":"F5","text":"Represents 29,513 shares of Series B Common Stock automatically converted into shares of Series A Common Stock in connection with tax withholding obligations related to the vesting and settlement of restricted stock units (\"RSUs\")."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F8","text":"Consists of (i) 267,030 shares of Series B Common Stock and (ii) 34,375 unvested RSUs awarded under the Issuer's 2015 Stock Incentive Plan, each representing the contingent right to receive one share of Series B Common Stock upon vesting and settlement."}],"balance_after":301405,"derivative":{"underlying":"Series A Common Stock","underlying_shares":29513},"source":{"system":"sec-edgar","filing":"0001470831-26-000157","document":"wk-form4_1771449150.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":7,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083126000157/wk-form4_1771449150.xml","form_type":"4"}},{"id":895525,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series B Common Stock","published_at":"2026-02-18T21:12:33.000Z","date":"2026-02-13","kind":"exercise","planned":true,"acquired":false,"shares":14000,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 21, 2025."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."}],"balance_after":330918,"derivative":{"underlying":"Series A Common Stock","underlying_shares":14000},"source":{"system":"sec-edgar","filing":"0001470831-26-000157","document":"wk-form4_1771449150.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":6,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083126000157/wk-form4_1771449150.xml","form_type":"4"}},{"id":895524,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2026-02-18T21:12:33.000Z","date":"2026-02-15","kind":"tax_withholding","planned":true,"acquired":false,"shares":45307,"price":18.6,"value":842710.2,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F6","text":"Represents shares of Series A Common Stock withheld by the Issuer to satisfy tax withholding obligations in connection with the vesting and settlement of RSUs."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F7","text":"Consists of (i) 66,394 shares of Series A Common Stock and (ii) 360,031 unvested RSUs awarded under the Issuer's 2023 Stock Option and Incentive Plan, each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement."}],"balance_after":426425,"source":{"system":"sec-edgar","filing":"0001470831-26-000157","document":"wk-form4_1771449150.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":5,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083126000157/wk-form4_1771449150.xml","form_type":"4"}},{"id":895523,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2026-02-18T21:12:33.000Z","date":"2026-02-15","kind":"exercise","planned":true,"acquired":true,"shares":29513,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F5","text":"Represents 29,513 shares of Series B Common Stock automatically converted into shares of Series A Common Stock in connection with tax withholding obligations related to the vesting and settlement of restricted stock units (\"RSUs\")."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."}],"balance_after":471732,"source":{"system":"sec-edgar","filing":"0001470831-26-000157","document":"wk-form4_1771449150.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083126000157/wk-form4_1771449150.xml","form_type":"4"}},{"id":895522,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2026-02-18T21:12:33.000Z","date":"2026-02-13","kind":"sale","planned":true,"acquired":false,"shares":4719,"price":18.63,"value":87914.97,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 21, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F4","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $18.52 to $18.75 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":442219,"source":{"system":"sec-edgar","filing":"0001470831-26-000157","document":"wk-form4_1771449150.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083126000157/wk-form4_1771449150.xml","form_type":"4"}},{"id":895521,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2026-02-18T21:12:33.000Z","date":"2026-02-13","kind":"sale","planned":true,"acquired":false,"shares":9281,"price":19.01,"value":176431.81,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 21, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F3","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $18.76 to $19.75 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":446938,"source":{"system":"sec-edgar","filing":"0001470831-26-000157","document":"wk-form4_1771449150.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083126000157/wk-form4_1771449150.xml","form_type":"4"}},{"id":895520,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2026-02-18T21:12:33.000Z","date":"2026-02-13","kind":"exercise","planned":true,"acquired":true,"shares":14000,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 21, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."}],"balance_after":456219,"source":{"system":"sec-edgar","filing":"0001470831-26-000157","document":"wk-form4_1771449150.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083126000157/wk-form4_1771449150.xml","form_type":"4"}},{"id":936685,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series B Common Stock","published_at":"2026-01-16T21:06:01.000Z","date":"2026-01-15","kind":"exercise","planned":true,"acquired":false,"shares":4045,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 21, 2025."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F6","text":"Consists of (i) 235,543 shares of Series B Common Stock and (ii) 109,375 unvested RSUs awarded under the Issuer's 2015 Stock Incentive Plan, each representing the contingent right to receive one share of Series B Common Stock upon vesting and settlement."}],"balance_after":344918,"derivative":{"underlying":"Series A Common Stock","underlying_shares":4045},"source":{"system":"sec-edgar","filing":"0001470831-26-000041","document":"wk-form4_1768597559.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083126000041/wk-form4_1768597559.xml","form_type":"4"}},{"id":936684,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2026-01-16T21:06:01.000Z","date":"2026-01-15","kind":"sale","planned":true,"acquired":false,"shares":6174,"price":25.52,"value":157560.48,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 21, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F4","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $25.295 to $25.68 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F5","text":"Consists of (i) 42,687 shares of Series A Common Stock and (ii) 399,532 unvested restricted stock units (\"RSUs\") awarded under the Issuer's 2023 Stock Option and Incentive Plan, each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement."}],"balance_after":442219,"source":{"system":"sec-edgar","filing":"0001470831-26-000041","document":"wk-form4_1768597559.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083126000041/wk-form4_1768597559.xml","form_type":"4"}},{"id":936683,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2026-01-16T21:06:01.000Z","date":"2026-01-15","kind":"sale","planned":true,"acquired":false,"shares":7826,"price":26.08,"value":204102.08,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 21, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F3","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $25.78 to $26.73 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":448393,"source":{"system":"sec-edgar","filing":"0001470831-26-000041","document":"wk-form4_1768597559.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083126000041/wk-form4_1768597559.xml","form_type":"4"}},{"id":936682,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2026-01-16T21:06:01.000Z","date":"2026-01-15","kind":"exercise","planned":true,"acquired":true,"shares":4045,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 21, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."}],"balance_after":456219,"source":{"system":"sec-edgar","filing":"0001470831-26-000041","document":"wk-form4_1768597559.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083126000041/wk-form4_1768597559.xml","form_type":"4"}},{"id":961709,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-12-19T21:06:25.000Z","date":"2025-12-18","kind":"sale","planned":true,"acquired":false,"shares":460,"price":30.59,"value":14071.4,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 21, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F3","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $30.45 to $30.63 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F4","text":"Consists of (i) 52,642 shares of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and (ii) 399,532 unvested restricted stock units awarded under the Issuer's 2023 Stock Option and Incentive Plan, each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement."}],"balance_after":452174,"source":{"system":"sec-edgar","filing":"0001470831-25-000444","document":"wk-form4_1766178380.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000444/wk-form4_1766178380.xml","form_type":"4"}},{"id":961708,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-12-19T21:06:25.000Z","date":"2025-12-18","kind":"sale","planned":true,"acquired":false,"shares":13540,"price":31.41,"value":425291.4,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 21, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $30.64 to $31.63 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":452634,"source":{"system":"sec-edgar","filing":"0001470831-25-000444","document":"wk-form4_1766178380.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000444/wk-form4_1766178380.xml","form_type":"4"}},{"id":994969,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series B Common Stock","published_at":"2025-11-18T21:07:10.000Z","date":"2025-11-15","kind":"exercise","planned":true,"acquired":false,"shares":29513,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"kind","element":"transactionCoding","label":"F5","text":"Represents 29,513 shares of Series B Common Stock automatically converted into shares of Series A Common Stock in connection with tax withholding obligations related to the vesting and settlement of restricted stock units (\"RSUs\")."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F8","text":"Consists of (i) 239,588 shares of Series B Common Stock and (ii) 109,375 unvested RSUs awarded under the Issuer's 2015 Stock Incentive Plan, each representing the contingent right to receive one share of Series B Common Stock upon vesting and settlement."}],"balance_after":348963,"derivative":{"underlying":"Series A Common Stock","underlying_shares":29513},"source":{"system":"sec-edgar","filing":"0001470831-25-000332","document":"wk-form4_1763500027.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":7,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000332/wk-form4_1763500027.xml","form_type":"4"}},{"id":994968,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series B Common Stock","published_at":"2025-11-18T21:07:10.000Z","date":"2025-11-14","kind":"exercise","planned":true,"acquired":false,"shares":15000,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."}],"balance_after":378476,"derivative":{"underlying":"Series A Common Stock","underlying_shares":15000},"source":{"system":"sec-edgar","filing":"0001470831-25-000332","document":"wk-form4_1763500027.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":6,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000332/wk-form4_1763500027.xml","form_type":"4"}},{"id":994967,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-11-18T21:07:10.000Z","date":"2025-11-15","kind":"tax_withholding","planned":true,"acquired":false,"shares":45058,"price":28.61,"value":1289109.38,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F6","text":"Represents shares of Series A Common Stock withheld by the Issuer to satisfy tax withholding obligations in connection with the vesting and settlement of RSUs."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F7","text":"Consists of (i) 66,642 shares of Series A Common Stock and (ii) 399,532 unvested RSUs awarded under the Issuer's 2023 Stock Option and Incentive Plan, each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement."}],"balance_after":466174,"source":{"system":"sec-edgar","filing":"0001470831-25-000332","document":"wk-form4_1763500027.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":5,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000332/wk-form4_1763500027.xml","form_type":"4"}},{"id":994966,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-11-18T21:07:10.000Z","date":"2025-11-15","kind":"exercise","planned":true,"acquired":true,"shares":29513,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F5","text":"Represents 29,513 shares of Series B Common Stock automatically converted into shares of Series A Common Stock in connection with tax withholding obligations related to the vesting and settlement of restricted stock units (\"RSUs\")."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."}],"balance_after":511232,"source":{"system":"sec-edgar","filing":"0001470831-25-000332","document":"wk-form4_1763500027.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000332/wk-form4_1763500027.xml","form_type":"4"}},{"id":994965,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-11-18T21:07:10.000Z","date":"2025-11-14","kind":"sale","planned":true,"acquired":false,"shares":300,"price":27.89,"value":8367.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"price","element":"transactionPricePerShare","label":"F4","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $27.805 to $27.95 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":481719,"source":{"system":"sec-edgar","filing":"0001470831-25-000332","document":"wk-form4_1763500027.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000332/wk-form4_1763500027.xml","form_type":"4"}},{"id":994964,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-11-18T21:07:10.000Z","date":"2025-11-14","kind":"sale","planned":true,"acquired":false,"shares":14700,"price":28.61,"value":420567.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"price","element":"transactionPricePerShare","label":"F3","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $27.96 to $28.95 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":482019,"source":{"system":"sec-edgar","filing":"0001470831-25-000332","document":"wk-form4_1763500027.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000332/wk-form4_1763500027.xml","form_type":"4"}},{"id":994963,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-11-18T21:07:10.000Z","date":"2025-11-14","kind":"exercise","planned":true,"acquired":true,"shares":15000,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."}],"balance_after":496719,"source":{"system":"sec-edgar","filing":"0001470831-25-000332","document":"wk-form4_1763500027.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000332/wk-form4_1763500027.xml","form_type":"4"}},{"id":1019872,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series B Common Stock","published_at":"2025-10-10T21:36:15.000Z","date":"2025-10-10","kind":"exercise","planned":true,"acquired":false,"shares":15000,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F6","text":"Consists of (i) 209,101 shares of Series B Common Stock and (ii) 184,375 unvested RSUs awarded under the Issuer's 2015 Stock Incentive Plan, each representing the contingent right to receive one share of Series B Common Stock upon vesting and settlement."}],"balance_after":393476,"derivative":{"underlying":"Series A Common Stock","underlying_shares":15000},"source":{"system":"sec-edgar","filing":"0001470831-25-000254","document":"wk-form4_1760132172.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000254/wk-form4_1760132172.xml","form_type":"4"}},{"id":1019871,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-10-10T21:36:15.000Z","date":"2025-10-10","kind":"sale","planned":true,"acquired":false,"shares":5192,"price":24.45,"value":126944.4,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"price","element":"transactionPricePerShare","label":"F4","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $24.25 to $24.73 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F5","text":"Consists of (i) 42,687 shares of Series A Common Stock and (ii) 439,032 unvested restricted stock units (\"RSUs\") awarded under the Issuer's 2023 Stock Option and Incentive Plan, each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement."}],"balance_after":481719,"source":{"system":"sec-edgar","filing":"0001470831-25-000254","document":"wk-form4_1760132172.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000254/wk-form4_1760132172.xml","form_type":"4"}},{"id":1019870,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-10-10T21:36:15.000Z","date":"2025-10-10","kind":"sale","planned":true,"acquired":false,"shares":9808,"price":25.33,"value":248436.64,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"price","element":"transactionPricePerShare","label":"F3","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $24.93 to $25.85 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":486911,"source":{"system":"sec-edgar","filing":"0001470831-25-000254","document":"wk-form4_1760132172.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000254/wk-form4_1760132172.xml","form_type":"4"}},{"id":1019869,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-10-10T21:36:15.000Z","date":"2025-10-10","kind":"exercise","planned":true,"acquired":true,"shares":15000,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."}],"balance_after":496719,"source":{"system":"sec-edgar","filing":"0001470831-25-000254","document":"wk-form4_1760132172.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000254/wk-form4_1760132172.xml","form_type":"4"}},{"id":1041157,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series B Common Stock","published_at":"2025-09-12T22:10:00.000Z","date":"2025-09-12","kind":"exercise","planned":true,"acquired":false,"shares":11204,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F5","text":"Consists of (i) 224,101 shares of Series B Common Stock and (ii) 184,375 unvested RSUs awarded under the Issuer's 2015 Stock Incentive Plan, each representing the contingent right to receive one share of Series B Common Stock upon vesting and settlement."}],"balance_after":408476,"derivative":{"underlying":"Series A Common Stock","underlying_shares":11204},"source":{"system":"sec-edgar","filing":"0001470831-25-000197","document":"wk-form4_1757714997.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000197/wk-form4_1757714997.xml","form_type":"4"}},{"id":1041156,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-09-12T22:10:00.000Z","date":"2025-09-12","kind":"sale","planned":true,"acquired":false,"shares":15000,"price":31.5,"value":472500.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"price","element":"transactionPricePerShare","label":"F3","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $31.17 to $31.98 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F4","text":"Consists of (i)  42,687 shares of Series A Common Stock and (ii) 439,032 unvested restricted stock units (\"RSUs\") awarded under the Issuer's 2023 Stock Option and Incentive Plan, each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement."}],"balance_after":481719,"source":{"system":"sec-edgar","filing":"0001470831-25-000197","document":"wk-form4_1757714997.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000197/wk-form4_1757714997.xml","form_type":"4"}},{"id":1041155,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-09-12T22:10:00.000Z","date":"2025-09-12","kind":"exercise","planned":true,"acquired":true,"shares":11204,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."}],"balance_after":496719,"source":{"system":"sec-edgar","filing":"0001470831-25-000197","document":"wk-form4_1757714997.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000197/wk-form4_1757714997.xml","form_type":"4"}},{"id":1061047,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series B Common Stock","published_at":"2025-08-20T00:51:10.000Z","date":"2025-08-15","kind":"exercise","planned":true,"acquired":false,"shares":29513,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F2","text":"Each share of Series B Common Stock is convertible at any time at the option of the holder into one share of Series A Common Stock and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"kind","element":"transactionCoding","label":"F1","text":"Represents 29,513 shares of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), automatically converted into shares of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), in connection with tax withholding obligations related to the vesting and settlement of restricted stock units (\"RSUs\")."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"Each share of Series B Common Stock is convertible at any time at the option of the holder into one share of Series A Common Stock and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"Each share of Series B Common Stock is convertible at any time at the option of the holder into one share of Series A Common Stock and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F7","text":"Consists of (i) 235,305 shares of Series B Common Stock and (ii) 184,375 unvested RSUs awarded under the Issuer's 2015 Stock Incentive Plan, each representing the contingent right to receive one share of Series B Common Stock upon vesting and settlement."}],"balance_after":419680,"derivative":{"underlying":"Series A Common Stock","underlying_shares":29513},"source":{"system":"sec-edgar","filing":"0001470831-25-000142","document":"wk-form4_1755651065.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000142/wk-form4_1755651065.xml","form_type":"4"}},{"id":1061046,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-08-20T00:51:10.000Z","date":"2025-08-15","kind":"sale","planned":true,"acquired":false,"shares":15000,"price":31.32,"value":469800.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F4","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"price","element":"transactionPricePerShare","label":"F5","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $30.92 to $31.53 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F6","text":"Consists of (i) 46,483 shares of Series A Common Stock and (ii) 439,032 unvested RSUs awarded under the Issuer's 2023 Stock Option and Incentive Plan, each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement."}],"balance_after":485515,"source":{"system":"sec-edgar","filing":"0001470831-25-000142","document":"wk-form4_1755651065.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000142/wk-form4_1755651065.xml","form_type":"4"}},{"id":1061045,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-08-20T00:51:10.000Z","date":"2025-08-15","kind":"tax_withholding","planned":true,"acquired":false,"shares":46829,"price":31.43,"value":1471835.47,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F3","text":"Represents shares of the Series A Common Stock withheld by the Issuer to satisfy tax withholding obligations in connection with the vesting and settlement of RSUs."}],"balance_after":500515,"source":{"system":"sec-edgar","filing":"0001470831-25-000142","document":"wk-form4_1755651065.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000142/wk-form4_1755651065.xml","form_type":"4"}},{"id":1061044,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-08-20T00:51:10.000Z","date":"2025-08-15","kind":"exercise","planned":true,"acquired":true,"shares":29513,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"Represents 29,513 shares of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), automatically converted into shares of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), in connection with tax withholding obligations related to the vesting and settlement of restricted stock units (\"RSUs\")."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"Each share of Series B Common Stock is convertible at any time at the option of the holder into one share of Series A Common Stock and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."}],"balance_after":547344,"source":{"system":"sec-edgar","filing":"0001470831-25-000142","document":"wk-form4_1755651065.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000142/wk-form4_1755651065.xml","form_type":"4"}},{"id":1087845,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series B Common Stock","published_at":"2025-07-14T20:09:04.000Z","date":"2025-07-11","kind":"exercise","planned":true,"acquired":false,"shares":15000,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A\nCommon Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the\nIssuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A\nCommon Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the\nIssuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A\nCommon Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the\nIssuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F5","text":"Consists of (i) 189,818 shares of Series B Common Stock and (ii) 259,375 unvested RSUs awarded under the Issuer's 2015 Stock Incentive Plan, each representing the contingent right to\nreceive one share of Series B Common Stock upon vesting and settlement."}],"balance_after":449193,"derivative":{"underlying":"Series A Common Stock","underlying_shares":15000},"source":{"system":"sec-edgar","filing":"0001470831-25-000082","document":"wk-form4_1752523733.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000082/wk-form4_1752523733.xml","form_type":"4"}},{"id":1087844,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-07-14T20:09:04.000Z","date":"2025-07-11","kind":"sale","planned":true,"acquired":false,"shares":200,"price":31.32,"value":6264.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F4","text":"Consists of (i) 34,799 shares of Series A Common Stock and (ii) 483,032 unvested restricted stock units (\"RSUs\") awarded under the Issuer's 2023 Stock Option and Incentive Plan, each representing\nthe contingent right to receive one share of Series A Common Stock upon vesting and settlement."}],"balance_after":517831,"source":{"system":"sec-edgar","filing":"0001470831-25-000082","document":"wk-form4_1752523733.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000082/wk-form4_1752523733.xml","form_type":"4"}},{"id":1087843,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-07-14T20:09:04.000Z","date":"2025-07-11","kind":"sale","planned":true,"acquired":false,"shares":14800,"price":31.66,"value":468568.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"price","element":"transactionPricePerShare","label":"F3","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $31.33 to $32.32 per share. The Reporting Person undertakes to\nprovide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price\nwithin the range set forth in this footnote."}],"balance_after":518031,"source":{"system":"sec-edgar","filing":"0001470831-25-000082","document":"wk-form4_1752523733.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000082/wk-form4_1752523733.xml","form_type":"4"}},{"id":1087842,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-07-14T20:09:04.000Z","date":"2025-07-11","kind":"exercise","planned":true,"acquired":true,"shares":15000,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A\nCommon Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the\nIssuer's certificate of incorporation. The Series B Common Stock has no expiration date."}],"balance_after":532831,"source":{"system":"sec-edgar","filing":"0001470831-25-000082","document":"wk-form4_1752523733.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000082/wk-form4_1752523733.xml","form_type":"4"}},{"id":1110742,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series B Common Stock","published_at":"2025-06-13T22:55:37.000Z","date":"2025-06-13","kind":"exercise","planned":true,"acquired":false,"shares":11204,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F5","text":"Consists of (i) 204,818 shares of the Issuer's Series B Common Stock and (ii) 259,375 unvested RSUs awarded under the Issuer's 2015 Stock Incentive Plan, each representing the contingent right to receive one share of Series B Common Stock upon vesting and settlement."}],"balance_after":464193,"derivative":{"underlying":"Series A Common Stock","underlying_shares":11204},"source":{"system":"sec-edgar","filing":"0001835830-25-000070","document":"wk-form4_1749855331.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583025000070/wk-form4_1749855331.xml","form_type":"4"}},{"id":1110741,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-06-13T22:55:37.000Z","date":"2025-06-13","kind":"sale","planned":true,"acquired":false,"shares":15000,"price":33.47,"value":502050.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"price","element":"transactionPricePerShare","label":"F3","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $33.14 to $33.92 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F4","text":"Consists of (i) 34,799 shares of Series A Common Stock and (ii) 483,032 unvested restricted stock units (\"RSUs\") awarded under the Issuer's 2023 Stock Option and Incentive Plan, each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement."}],"balance_after":517831,"source":{"system":"sec-edgar","filing":"0001835830-25-000070","document":"wk-form4_1749855331.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583025000070/wk-form4_1749855331.xml","form_type":"4"}},{"id":1110740,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-06-13T22:55:37.000Z","date":"2025-06-13","kind":"exercise","planned":true,"acquired":true,"shares":11204,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."}],"balance_after":532831,"source":{"system":"sec-edgar","filing":"0001835830-25-000070","document":"wk-form4_1749855331.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583025000070/wk-form4_1749855331.xml","form_type":"4"}},{"id":1144613,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series B Common Stock","published_at":"2025-05-17T00:41:31.000Z","date":"2025-05-15","kind":"exercise","planned":true,"acquired":false,"shares":29513,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F2","text":"Each share of Series B Common Stock is convertible at any time at the option of the holder into one share of Series A Common Stock and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"kind","element":"transactionCoding","label":"F1","text":"Represents 29,513 shares of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), automatically converted into shares of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), in connection with tax withholding obligations related to the vesting and settlement of restricted stock units (\"RSUs\")."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"Each share of Series B Common Stock is convertible at any time at the option of the holder into one share of Series A Common Stock and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"Each share of Series B Common Stock is convertible at any time at the option of the holder into one share of Series A Common Stock and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F7","text":"Consists of (i) 216,022 shares of Series B Common Stock and (ii) 259,375 unvested RSUs awarded under the Issuer's 2015 Stock Incentive Plan, each representing the contingent right to receive one share of Series B Common Stock upon vesting and settlement."}],"balance_after":475397,"derivative":{"underlying":"Series A Common Stock","underlying_shares":29513},"source":{"system":"sec-edgar","filing":"0001835830-25-000055","document":"wk-form4_1747442485.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583025000055/wk-form4_1747442485.xml","form_type":"4"}},{"id":1144612,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-05-17T00:41:31.000Z","date":"2025-05-16","kind":"sale","planned":true,"acquired":false,"shares":15000,"price":34.98,"value":524700.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F4","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"price","element":"transactionPricePerShare","label":"F5","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $34.50 to $35.37 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F6","text":"Consists of (i) 38,595 shares of Series A Common Stock and (ii) 483,032 unvested RSUs awarded under the Issuer's 2023 Stock Option and Incentive Plan, each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement."}],"balance_after":521627,"source":{"system":"sec-edgar","filing":"0001835830-25-000055","document":"wk-form4_1747442485.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583025000055/wk-form4_1747442485.xml","form_type":"4"}},{"id":1144611,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-05-17T00:41:31.000Z","date":"2025-05-15","kind":"tax_withholding","planned":true,"acquired":false,"shares":46829,"price":34.9,"value":1634332.1,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F3","text":"Represents shares of Series A Common Stock withheld by the Issuer to satisfy tax withholding obligations in connection with the vesting and settlement of RSUs."}],"balance_after":536627,"source":{"system":"sec-edgar","filing":"0001835830-25-000055","document":"wk-form4_1747442485.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583025000055/wk-form4_1747442485.xml","form_type":"4"}},{"id":1144610,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-05-17T00:41:31.000Z","date":"2025-05-15","kind":"exercise","planned":true,"acquired":true,"shares":29513,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"Represents 29,513 shares of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), automatically converted into shares of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), in connection with tax withholding obligations related to the vesting and settlement of restricted stock units (\"RSUs\")."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"Each share of Series B Common Stock is convertible at any time at the option of the holder into one share of Series A Common Stock and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."}],"balance_after":583456,"source":{"system":"sec-edgar","filing":"0001835830-25-000055","document":"wk-form4_1747442485.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583025000055/wk-form4_1747442485.xml","form_type":"4"}},{"id":1173090,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series B Common Stock","published_at":"2025-04-11T23:10:35.000Z","date":"2025-04-11","kind":"exercise","planned":true,"acquired":false,"shares":11204,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into shares of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into shares of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into shares of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F6","text":"Consists of (i) 170,535 shares of the Series B Common Stock, and (ii) 334,375 unvested RSUs awarded under the Issuer's 2015 Stock Incentive Plan, each representing the contingent right to receive one share of Series B Common Stock upon vesting and settlement."}],"balance_after":504910,"derivative":{"underlying":"Series A Common Stock","underlying_shares":11204},"source":{"system":"sec-edgar","filing":"0001835830-25-000034","document":"wk-form4_1744413027.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583025000034/wk-form4_1744413027.xml","form_type":"4"}},{"id":1173089,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-04-11T23:10:35.000Z","date":"2025-04-11","kind":"sale","planned":true,"acquired":false,"shares":3400,"price":26.2,"value":89080.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"price","element":"transactionPricePerShare","label":"F4","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $25.96 to $26.31 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F5","text":"Consists of (i) 26,911 shares of the Series A Common Stock and (ii) 527,032 unvested restricted stock units (\"RSUs\") awarded under the Issuer's 2023 Stock Option and Incentive Plan, each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement."}],"balance_after":553943,"source":{"system":"sec-edgar","filing":"0001835830-25-000034","document":"wk-form4_1744413027.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583025000034/wk-form4_1744413027.xml","form_type":"4"}},{"id":1173088,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-04-11T23:10:35.000Z","date":"2025-04-11","kind":"sale","planned":true,"acquired":false,"shares":11600,"price":26.85,"value":311460.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"price","element":"transactionPricePerShare","label":"F3","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $26.34 to $27.31 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":557343,"source":{"system":"sec-edgar","filing":"0001835830-25-000034","document":"wk-form4_1744413027.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583025000034/wk-form4_1744413027.xml","form_type":"4"}},{"id":1173087,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-04-11T23:10:35.000Z","date":"2025-04-11","kind":"exercise","planned":true,"acquired":true,"shares":11204,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into shares of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."}],"balance_after":568943,"source":{"system":"sec-edgar","filing":"0001835830-25-000034","document":"wk-form4_1744413027.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583025000034/wk-form4_1744413027.xml","form_type":"4"}},{"id":1198145,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-03-18T22:57:04.000Z","date":"2025-03-17","kind":"grant","planned":true,"acquired":true,"shares":208116,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F3","text":"Represents restricted stock units (\"RSUs\") awarded under the Issuer's 2023 Stock Option and Incentive Plan, each representing the contingent right to receive one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), upon vesting and settlement. The RSUs vest as follows: (i) 50% of the RSUs will vest in eight equal quarterly installments, with the first such installment vesting on May 15, 2025, and (ii) thereafter the remaining 50% of the RSUs will vest in four equal quarterly installments, subject to the Reporting Person's continued service on each such vesting date."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F4","text":"Consists of (i) 30,707 shares of Series A Common Stock and (ii) 527,032 unvested RSUs awarded under the Issuer's 2023 Stock Option and Incentive Plan, each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement."}],"balance_after":557739,"source":{"system":"sec-edgar","filing":"0001835830-25-000032","document":"wk-form4_1742338617.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583025000032/wk-form4_1742338617.xml","form_type":"4"}},{"id":1198144,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-03-18T22:57:04.000Z","date":"2025-03-14","kind":"sale","planned":true,"acquired":false,"shares":25,"price":32.92,"value":823.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."}],"balance_after":349623,"source":{"system":"sec-edgar","filing":"0001835830-25-000032","document":"wk-form4_1742338617.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583025000032/wk-form4_1742338617.xml","form_type":"4"}},{"id":1198143,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-03-18T22:57:04.000Z","date":"2025-03-14","kind":"sale","planned":true,"acquired":false,"shares":14975,"price":33.54,"value":502261.5,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $32.95 to $33.93 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":349648,"source":{"system":"sec-edgar","filing":"0001835830-25-000032","document":"wk-form4_1742338617.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583025000032/wk-form4_1742338617.xml","form_type":"4"}},{"id":1258397,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series B Common Stock","published_at":"2025-02-19T22:51:24.000Z","date":"2025-02-15","kind":"exercise","planned":false,"acquired":false,"shares":18944,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F2","text":"Each share of Series B Common Stock is convertible at any time at the option of the holder into one share of Series A Common Stock and will automatically convert into shares of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"kind","element":"transactionCoding","label":"F1","text":"Represents 18,944 shares of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), automatically converted into shares of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), in connection with tax withholding obligations related to the vesting and settlement of restricted stock units (\"RSUs\")."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"Each share of Series B Common Stock is convertible at any time at the option of the holder into one share of Series A Common Stock and will automatically convert into shares of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"Each share of Series B Common Stock is convertible at any time at the option of the holder into one share of Series A Common Stock and will automatically convert into shares of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F5","text":"Consists of (i) 181,739 shares of Series B Common Stock and (ii) 334,375 unvested RSUs awarded under the Issuer's 2015 Stock Incentive Plan, each representing the contingent right to receive one share of Series B Common Stock upon vesting and settlement."}],"balance_after":516114,"derivative":{"underlying":"Series A Common Stock","underlying_shares":18944},"source":{"system":"sec-edgar","filing":"0001835830-25-000021","document":"wk-form4_1740005478.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583025000021/wk-form4_1740005478.xml","form_type":"4"}},{"id":1258396,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-02-19T22:51:24.000Z","date":"2025-02-15","kind":"tax_withholding","planned":false,"acquired":false,"shares":31141,"price":47,"value":1463627.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F3","text":"Represents shares of Series A Common Stock withheld by the Issuer to satisfy tax withholding obligations in connection with the vesting and settlement of RSUs."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F4","text":"Consists of (i) 45,707 shares of Series A Common Stock and (ii) 318,916 unvested RSUs awarded under the Issuer's 2023 Stock Option and Incentive Plan, each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement."}],"balance_after":364623,"source":{"system":"sec-edgar","filing":"0001835830-25-000021","document":"wk-form4_1740005478.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583025000021/wk-form4_1740005478.xml","form_type":"4"}},{"id":1258395,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-02-19T22:51:24.000Z","date":"2025-02-15","kind":"exercise","planned":false,"acquired":true,"shares":18944,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"Represents 18,944 shares of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), automatically converted into shares of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), in connection with tax withholding obligations related to the vesting and settlement of restricted stock units (\"RSUs\")."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"Each share of Series B Common Stock is convertible at any time at the option of the holder into one share of Series A Common Stock and will automatically convert into shares of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."}],"balance_after":395764,"source":{"system":"sec-edgar","filing":"0001835830-25-000021","document":"wk-form4_1740005478.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583025000021/wk-form4_1740005478.xml","form_type":"4"}},{"id":1283395,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-02-04T21:26:59.000Z","date":"2025-02-03","kind":"sale","planned":true,"acquired":false,"shares":1700,"price":44.54,"value":75718.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"price","element":"transactionPricePerShare","label":"F4","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $44.19 to $44.73 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F5","text":"Consists of (i) 26,911 shares of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and (ii) 349,909 unvested restricted stock units awarded under the Issuer's 2023 Stock Option and Incentive Plan, each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement."}],"balance_after":376820,"source":{"system":"sec-edgar","filing":"0001835830-25-000007","document":"wk-form4_1738704413.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583025000007/wk-form4_1738704413.xml","form_type":"4"}},{"id":1283394,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-02-04T21:26:59.000Z","date":"2025-02-03","kind":"sale","planned":true,"acquired":false,"shares":3516,"price":45,"value":158220.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"price","element":"transactionPricePerShare","label":"F3","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $44.74 to $45.73 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":378520,"source":{"system":"sec-edgar","filing":"0001835830-25-000007","document":"wk-form4_1738704413.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583025000007/wk-form4_1738704413.xml","form_type":"4"}},{"id":1283393,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-02-04T21:26:59.000Z","date":"2025-02-03","kind":"sale","planned":true,"acquired":false,"shares":9784,"price":46.39,"value":453879.76,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $45.77 to $46.76 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":382036,"source":{"system":"sec-edgar","filing":"0001835830-25-000007","document":"wk-form4_1738704413.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583025000007/wk-form4_1738704413.xml","form_type":"4"}},{"id":1304809,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series B Common Stock","published_at":"2025-01-10T23:58:35.000Z","date":"2025-01-10","kind":"exercise","planned":true,"acquired":false,"shares":15000,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into shares of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into shares of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into shares of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F6","text":"Consists of (i) 152,766 shares of Series B Common Stock and (ii) 382,292 unvested RSUs awarded under the Issuer's 2015 Stock Incentive Plan, each representing the contingent right to receive one share of Series B Common Stock upon vesting and settlement."}],"balance_after":535058,"derivative":{"underlying":"Series A Common Stock","underlying_shares":15000},"source":{"system":"sec-edgar","filing":"0001835830-25-000001","document":"wk-form4_1736553508.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583025000001/wk-form4_1736553508.xml","form_type":"4"}},{"id":1304808,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-01-10T23:58:35.000Z","date":"2025-01-10","kind":"sale","planned":true,"acquired":false,"shares":3541,"price":38.68,"value":136965.88,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"price","element":"transactionPricePerShare","label":"F4","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $38.34 to $38.89 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F5","text":"Consists of (i) 41,911 shares of Series A Common Stock and (ii) 349,909 unvested restricted stock units (\"RSUs\") awarded under the Issuer's 2023 Stock Option and Incentive Plan, each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement."}],"balance_after":391820,"source":{"system":"sec-edgar","filing":"0001835830-25-000001","document":"wk-form4_1736553508.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583025000001/wk-form4_1736553508.xml","form_type":"4"}},{"id":1304807,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-01-10T23:58:35.000Z","date":"2025-01-10","kind":"sale","planned":true,"acquired":false,"shares":11459,"price":39.34,"value":450797.06,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"price","element":"transactionPricePerShare","label":"F3","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $38.90 to $39.89 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":395361,"source":{"system":"sec-edgar","filing":"0001835830-25-000001","document":"wk-form4_1736553508.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583025000001/wk-form4_1736553508.xml","form_type":"4"}},{"id":1304806,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2025-01-10T23:58:35.000Z","date":"2025-01-10","kind":"exercise","planned":true,"acquired":true,"shares":15000,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into shares of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."}],"balance_after":406820,"source":{"system":"sec-edgar","filing":"0001835830-25-000001","document":"wk-form4_1736553508.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583025000001/wk-form4_1736553508.xml","form_type":"4"}},{"id":1331835,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series B Common Stock","published_at":"2024-12-14T01:49:12.000Z","date":"2024-12-13","kind":"exercise","planned":true,"acquired":false,"shares":11204,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into shares of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into shares of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into shares of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F5","text":"Consists of (i) 167,766 shares of Series B Common Stock and (ii) 382,292 unvested RSUs awarded under the Issuer's 2015 Stock Incentive Plan, each representing the contingent right to receive one share of Series B Common Stock upon vesting and settlement."}],"balance_after":550058,"derivative":{"underlying":"Series A Common Stock","underlying_shares":11204},"source":{"system":"sec-edgar","filing":"0001835830-24-000120","document":"wk-form4_1734140939.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583024000120/wk-form4_1734140939.xml","form_type":"4"}},{"id":1331834,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2024-12-14T01:49:12.000Z","date":"2024-12-13","kind":"sale","planned":true,"acquired":false,"shares":15000,"price":39.39,"value":590850.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"price","element":"transactionPricePerShare","label":"F3","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $39.02 to $39.83 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F4","text":"Consists of (i) 41,911 shares of Series A Common Stock and (ii) 349,909 unvested restricted stock units (\"RSUs\") awarded under the Issuer's 2023 Stock Option and Incentive Plan, each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement."}],"balance_after":391820,"source":{"system":"sec-edgar","filing":"0001835830-24-000120","document":"wk-form4_1734140939.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583024000120/wk-form4_1734140939.xml","form_type":"4"}},{"id":1331833,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2024-12-14T01:49:12.000Z","date":"2024-12-13","kind":"exercise","planned":true,"acquired":true,"shares":11204,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into shares of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."}],"balance_after":406820,"source":{"system":"sec-edgar","filing":"0001835830-24-000120","document":"wk-form4_1734140939.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583024000120/wk-form4_1734140939.xml","form_type":"4"}},{"id":1338486,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series B Common Stock","published_at":"2024-12-09T22:27:18.000Z","date":"2024-12-09","kind":"exercise","planned":true,"acquired":false,"shares":1050,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F6","text":"Consists of (i) 178,970 shares of Series B Common Stock and (ii) 382,292 unvested RSUs awarded under the Issuer's 2015 Stock Incentive Plan, each representing the contingent right to receive one share of Series B Common Stock upon vesting and settlement."}],"balance_after":561262,"derivative":{"underlying":"Series A Common Stock","underlying_shares":1050},"source":{"system":"sec-edgar","filing":"0001835830-24-000118","document":"wk-form4_1733783231.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":6,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583024000118/wk-form4_1733783231.xml","form_type":"4"}},{"id":1338485,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series B Common Stock","published_at":"2024-12-09T22:27:18.000Z","date":"2024-12-06","kind":"exercise","planned":true,"acquired":false,"shares":23950,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."}],"balance_after":562312,"derivative":{"underlying":"Series A Common Stock","underlying_shares":23950},"source":{"system":"sec-edgar","filing":"0001835830-24-000118","document":"wk-form4_1733783231.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":5,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583024000118/wk-form4_1733783231.xml","form_type":"4"}},{"id":1338484,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2024-12-09T22:27:18.000Z","date":"2024-12-09","kind":"sale","planned":true,"acquired":false,"shares":1050,"price":40.07,"value":42073.5,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"price","element":"transactionPricePerShare","label":"F4","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $40.00 to $40.15 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F5","text":"Consists of (i) 45,707 shares of Series A Common Stock and (ii) 349,909 unvested restricted stock units (\"RSUs\") awarded under the Issuer's 2023 Stock Option and Incentive Plan, each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement."}],"balance_after":395616,"source":{"system":"sec-edgar","filing":"0001835830-24-000118","document":"wk-form4_1733783231.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583024000118/wk-form4_1733783231.xml","form_type":"4"}},{"id":1338483,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2024-12-09T22:27:18.000Z","date":"2024-12-09","kind":"exercise","planned":true,"acquired":true,"shares":1050,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."}],"balance_after":396666,"source":{"system":"sec-edgar","filing":"0001835830-24-000118","document":"wk-form4_1733783231.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583024000118/wk-form4_1733783231.xml","form_type":"4"}},{"id":1338482,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2024-12-09T22:27:18.000Z","date":"2024-12-06","kind":"sale","planned":true,"acquired":false,"shares":23950,"price":40.04,"value":958958.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"price","element":"transactionPricePerShare","label":"F3","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $40.00 to $40.11 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":395616,"source":{"system":"sec-edgar","filing":"0001835830-24-000118","document":"wk-form4_1733783231.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583024000118/wk-form4_1733783231.xml","form_type":"4"}},{"id":1338481,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2024-12-09T22:27:18.000Z","date":"2024-12-06","kind":"exercise","planned":true,"acquired":true,"shares":23950,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."}],"balance_after":419566,"source":{"system":"sec-edgar","filing":"0001835830-24-000118","document":"wk-form4_1733783231.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583024000118/wk-form4_1733783231.xml","form_type":"4"}},{"id":1358148,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series B Common Stock","published_at":"2024-11-19T23:09:37.000Z","date":"2024-11-15","kind":"exercise","planned":true,"acquired":false,"shares":18856,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F2","text":"Each share of Series B Common Stock is convertible at any time at the option of the holder into one share of Series A Common Stock, and will automatically convert into Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"kind","element":"transactionCoding","label":"F1","text":"Represents 18,856 shares of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), automatically converted into  shares of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), in connection with tax withholding obligations relating to the vesting and settlement of restricted stock units (\"RSUs\")."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"Each share of Series B Common Stock is convertible at any time at the option of the holder into one share of Series A Common Stock, and will automatically convert into Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"Each share of Series B Common Stock is convertible at any time at the option of the holder into one share of Series A Common Stock, and will automatically convert into Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F7","text":"Consists of (i) 203,970 shares of Series B Common Stock and (ii) 382,292 unvested RSUs awarded under the Issuer's 2015 Stock Incentive Plan, each representing the contingent right to receive one share of Series B Common Stock upon vesting and settlement."}],"balance_after":586262,"derivative":{"underlying":"Series A Common Stock","underlying_shares":18856},"source":{"system":"sec-edgar","filing":"0001835830-24-000112","document":"wk-form4_1732057767.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583024000112/wk-form4_1732057767.xml","form_type":"4"}},{"id":1358147,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2024-11-19T23:09:37.000Z","date":"2024-11-18","kind":"sale","planned":true,"acquired":false,"shares":15000,"price":34.56,"value":518400.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F4","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 16, 2024."},{"field":"price","element":"transactionPricePerShare","label":"F5","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $34.16 to $35.00 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F6","text":"Consists of (i) 45,707 shares of Series A Common Stock and (ii) 349,909 unvested RSUs awarded under the Issuer's 2023 Stock Option and Incentive Plan, each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement."}],"balance_after":395616,"source":{"system":"sec-edgar","filing":"0001835830-24-000112","document":"wk-form4_1732057767.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583024000112/wk-form4_1732057767.xml","form_type":"4"}},{"id":1358146,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2024-11-19T23:09:37.000Z","date":"2024-11-15","kind":"tax_withholding","planned":true,"acquired":false,"shares":31053,"price":35.16,"value":1091823.48,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F3","text":"Represents shares of Series A Common Stock withheld by the Issuer to satisfy tax withholding obligations in connection with the vesting and settlement of RSUs."}],"balance_after":410616,"source":{"system":"sec-edgar","filing":"0001835830-24-000112","document":"wk-form4_1732057767.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583024000112/wk-form4_1732057767.xml","form_type":"4"}},{"id":1358145,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2024-11-19T23:09:37.000Z","date":"2024-11-15","kind":"exercise","planned":true,"acquired":true,"shares":18856,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"Represents 18,856 shares of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), automatically converted into  shares of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), in connection with tax withholding obligations relating to the vesting and settlement of restricted stock units (\"RSUs\")."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"Each share of Series B Common Stock is convertible at any time at the option of the holder into one share of Series A Common Stock, and will automatically convert into Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."}],"balance_after":441669,"source":{"system":"sec-edgar","filing":"0001835830-24-000112","document":"wk-form4_1732057767.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583024000112/wk-form4_1732057767.xml","form_type":"4"}},{"id":1390538,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series B Common Stock","published_at":"2024-10-04T23:00:28.000Z","date":"2024-10-04","kind":"exercise","planned":true,"acquired":false,"shares":10000,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into shares of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on November 16, 2023."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into shares of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into shares of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F5","text":"Consists of (i) 174,909 shares of Series B Common Stock and (ii) 430,209 unvested RSUs awarded under the Issuer's 2015 Stock Incentive Plan, each representing the contingent right to receive one share of Series B Common Stock upon vesting and settlement."}],"balance_after":605118,"derivative":{"underlying":"Series A Common Stock","underlying_shares":10000},"source":{"system":"sec-edgar","filing":"0001835830-24-000099","document":"wk-form4_1728082822.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583024000099/wk-form4_1728082822.xml","form_type":"4"}},{"id":1390537,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2024-10-04T23:00:28.000Z","date":"2024-10-04","kind":"sale","planned":true,"acquired":false,"shares":10000,"price":35.36,"value":353600.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on November 16, 2023."},{"field":"price","element":"transactionPricePerShare","label":"F3","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $34.93 to $35.63 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F4","text":"Consists of (i) 41,911 shares of Series A Common Stock and (ii) 380,902 unvested restricted stock units (\"RSUs\") awarded under the Issuer's 2023 Stock Option and Incentive Plan, each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement."}],"balance_after":422813,"source":{"system":"sec-edgar","filing":"0001835830-24-000099","document":"wk-form4_1728082822.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583024000099/wk-form4_1728082822.xml","form_type":"4"}},{"id":1390536,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2024-10-04T23:00:28.000Z","date":"2024-10-04","kind":"exercise","planned":true,"acquired":true,"shares":10000,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on November 16, 2023."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into shares of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."}],"balance_after":432813,"source":{"system":"sec-edgar","filing":"0001835830-24-000099","document":"wk-form4_1728082822.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583024000099/wk-form4_1728082822.xml","form_type":"4"}},{"id":1412474,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series B Common Stock","published_at":"2024-09-07T00:13:26.000Z","date":"2024-09-06","kind":"exercise","planned":true,"acquired":false,"shares":10000,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F2","text":"Each share of Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), of the Issuer, and will automatically convert into shares of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on November 16, 2023."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"Each share of Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), of the Issuer, and will automatically convert into shares of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"Each share of Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), of the Issuer, and will automatically convert into shares of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F6","text":"Consists of (i) 184,909 shares of Series B Common Stock and (ii) 430,209 unvested RSUs awarded under the Issuer's 2015 Stock Incentive Plan, each representing the contingent right to receive one share of Series B Common Stock upon vesting and settlement."}],"balance_after":615118,"derivative":{"underlying":"Series A Common Stock","underlying_shares":10000},"source":{"system":"sec-edgar","filing":"0001835830-24-000093","document":"wk-form4_1725668000.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583024000093/wk-form4_1725668000.xml","form_type":"4"}},{"id":1412473,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2024-09-07T00:13:26.000Z","date":"2024-09-06","kind":"sale","planned":true,"acquired":false,"shares":200,"price":29.39,"value":5878.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on November 16, 2023."},{"field":"price","element":"transactionPricePerShare","label":"F4","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $29.35 to $29.42 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F5","text":"Consists of (i) 41,911 shares of Series A Common Stock and (ii) 380,902 unvested restricted stock units (\"RSUs\") awarded under the Issuer's 2023 Stock Option and Incentive Plan, each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement."}],"balance_after":422813,"source":{"system":"sec-edgar","filing":"0001835830-24-000093","document":"wk-form4_1725668000.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583024000093/wk-form4_1725668000.xml","form_type":"4"}},{"id":1412472,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2024-09-07T00:13:26.000Z","date":"2024-09-06","kind":"sale","planned":true,"acquired":false,"shares":9800,"price":29.73,"value":291354.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on November 16, 2023."},{"field":"price","element":"transactionPricePerShare","label":"F3","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $29.47 to $30.46 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":423013,"source":{"system":"sec-edgar","filing":"0001835830-24-000093","document":"wk-form4_1725668000.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583024000093/wk-form4_1725668000.xml","form_type":"4"}},{"id":1412471,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2024-09-07T00:13:26.000Z","date":"2024-09-06","kind":"exercise","planned":true,"acquired":true,"shares":10000,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on November 16, 2023."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"Each share of Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), of the Issuer, and will automatically convert into shares of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."}],"balance_after":432813,"source":{"system":"sec-edgar","filing":"0001835830-24-000093","document":"wk-form4_1725668000.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583024000093/wk-form4_1725668000.xml","form_type":"4"}},{"id":1430818,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series B Common Stock","published_at":"2024-08-16T23:45:06.000Z","date":"2024-08-15","kind":"exercise","planned":false,"acquired":false,"shares":18856,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F2","text":"Each share of Series B Common Stock is convertible at any time at the option of the holder into one share of Series A Common Stock, and will automatically convert into shares of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"kind","element":"transactionCoding","label":"F1","text":"Represents 18,856 shares of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), automatically converted into shares of the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), in connection with tax withholding obligations related to the vesting and settlement of restricted stock units (\"RSUs\")."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"Each share of Series B Common Stock is convertible at any time at the option of the holder into one share of Series A Common Stock, and will automatically convert into shares of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"Each share of Series B Common Stock is convertible at any time at the option of the holder into one share of Series A Common Stock, and will automatically convert into shares of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F5","text":"Consists of (i) 194,909 shares of Series B Common Stock and (ii) 430,209 unvested RSUs awarded under the Issuer's 2015 Stock Incentive Plan, each representing the contingent right to receive one share of Series B Common Stock upon vesting and settlement."}],"balance_after":625118,"derivative":{"underlying":"Series A Common Stock","underlying_shares":18856},"source":{"system":"sec-edgar","filing":"0001835830-24-000085","document":"wk-form4_1723851900.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583024000085/wk-form4_1723851900.xml","form_type":"4"}},{"id":1430817,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":21993,"kind":"person","name":"Whalen Amanda","position":1,"cik":"0001991131","reported_name":"Whalen Amanda","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Series A Common Stock","published_at":"2024-08-16T23:45:06.000Z","date":"2024-08-15","kind":"tax_withholding","planned":false,"acquired":false,"shares":32036,"price":31.83,"value":1019705.88,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F3","text":"Represents shares of Series A Common Stock withheld by the Issuer to satisfy tax withholding obligations in connection with the vesting and settlement of RSUs."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F4","text":"Consists of (i) 41,911 shares of Series A Common Stock and (ii) 380,902 unvested RSUs awarded under the Issuer's 2023 Stock Incentive Plan, each representing the contingent right to receive one share of Series A Common Stock upon vesting and settlement."}],"balance_after":422813,"source":{"system":"sec-edgar","filing":"0001835830-24-000085","document":"wk-form4_1723851900.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000183583024000085/wk-form4_1723851900.xml","form_type":"4"}}],"next_cursor":"2024-08-16T23:45:06.000000Z,1430817"}