144 0001856597 XXXXXXXX LIVE 0001496963 Squarespace, Inc. 001-40393 225 Varick Street 12th Floor New York NY 10014 1-646-580-3456 Anthony Casalena Officer Class A Common Stock Goldman Sachs & Co. LLC 200 West Street New York NY 10282 80202 2581702.38 88728441 03/07/2024 NYSE Class A Common Stock 08/18/2017 Acquired as compensation -- Restricted Stock Awards The Issuer N 80202 08/18/2017 Compensation N ANTHONY CASALENA REVOCABLE TRUST 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 01/26/2024 59935 1960198.15 ANTHONY CASALENA REVOCABLE TRUST 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 01/29/2024 66420 2149457.47 ANTHONY CASALENA REVOCABLE TRUST 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 02/08/2024 20000 635336 ANTHONY CASALENA REVOCABLE TRUST 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 02/09/2024 38587 1250658.69 ANTHONY CASALENA REVOCABLE TRUST 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 02/23/2024 9613 306575.87 ANTHONY CASALENA REVOCABLE TRUST 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 12/15/2023 67352 1923963.76 ANTHONY CASALENA REVOCABLE TRUST 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 02/22/2024 51349 1629560.51 ANTHONY CASALENA REVOCABLE TRUST 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 01/02/2024 38835 1230366.59 ANTHONY CASALENA REVOCABLE TRUST 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 01/12/2024 24603 793306.51 ANTHONY CASALENA REVOCABLE TRUST 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 02/23/2024 47995 1544795.87 ANTHONY CASALENA REVOCABLE TRUST 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 02/08/2024 6800 219497.88 ANTHONY CASALENA REVOCABLE TRUST 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 12/29/2023 22949 763150.64 ANTHONY CASALENA REVOCABLE TRUST 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 01/12/2024 11746 373895.15 ANTHONY CASALENA REVOCABLE TRUST 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 12/18/2023 32184 932570.02 ANTHONY CASALENA REVOCABLE TRUST 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 01/02/2024 2000 64169.6 ANTHONY CASALENA REVOCABLE TRUST 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 02/09/2024 1000 31937.2 ANTHONY CASALENA REVOCABLE TRUST 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 03/06/2024 51278 1613087.94 ANTHONY CASALENA REVOCABLE TRUST 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 01/16/2024 43539 1377373.68 ANTHONY CASALENA REVOCABLE TRUST 225 Varick Street 12th Floor New York NY 10014 Class A Common Stock 02/22/2024 15881 510323.23 The sales of shares set forth herein are made in connection with a selling plan dated 8/11/2023, that is intended to comply with Rule 10b5-1(c). All shares to be sold by the Anthony Casalena Revocable Trust. 03/07/2024 08/11/2023 Goldman Sachs & Co. LLC on behalf of Anthony Casalena