X0609 4 2026-09-16 0 0001517413 Fastly, Inc. FSLY 0001993556 Ford Jeffrey false C/O FASTLY, INC. 475 BRANNAN STREET, SUITE 300 SAN FRANCISCO CA 94107 0 1 0 0 Principal Accounting Officer 0 Class A Common Stock 2026-09-16 4 S 0 37091 23.84 D 295693 D Shares sold to satisfy tax obligations in connection with the vesting of previously granted Restricted Stock Units. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $23.84 to $24.04, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the SEC, upon request, full information regarding the number of shares sold at each separate price within the range set forth in footnote (2) to this Form 4. /s/ Tara Seracka, Attorney-in-Fact 2026-09-18