Fastly, Inc.

Trading Arrangements

During the Company’s last fiscal quarter, the Company’s directors and officers (as defined in Rule 16a-1(f) under the Exchange Act)adopted, terminated, or modified certain contracts, instructions or written plans intended to satisfy the affirmative defense of Rule 10b5-1(c) for the purchase or sale of the Company’s securities set forth in the table below.

(1) On June 4, 2026, Artur Bergman, the Company's Chief Technology Officer and member of the Company's Board of Directors, entered into a 10b5-1 Plan, providing for the potential sale of up to 1,917,993 shares of the Company's Common Stock. However, because certain of Mr. Bergman’s planned sale amounts are equal to a designated percentage of the net number of shares resulting (i) from RSUs vesting or (ii) from the Executive PSUs as detailed in Note 10 — Stockholders' Equity — Performance Stock Awards for Executive Officers (“Executive PSUs”), of which a portion will be surrendered to the Company or sold to cover withholding taxes, depending on how many shares are withheld in these instances, and the level of achievement of certain Company-wide targets related to the Company’s operating plan for the fiscal year 2026 (as it relates to the Executive PSUs), the maximum number of shares to be sold may be less. The plan expires on August 30, 2027, or upon the earlier completion of all authorized transactions under the plan.

(2) On May 11, 2026, Charles Compton, the Company's Chief Executive Officer and member of the Company's Board of Directors, entered into a 10b5-1 Plan, providing for the potential sale of up to 924,625 shares of the Company's Common Stock, plus any shares awarded under the Company’s 2026 Bonus Program as detailed in Note 10 — Stockholders' Equity — Company-wide Bonus Programs (“Bonus Programs”). However, the maximum number of shares to be sold may be less because certain of Mr. Compton’s planned sale amounts are equal to (i) a number of shares, or a designated percentage of shares, not otherwise sold under his previously disclosed Rule 10b5-1 plan, adopted on August 27, 2025, (ii) a designated percentage of the net number of shares resulting from RSUs vesting, or (iii) a designated percentage of the net number of shares resulting from the Executive PSUs as detailed in Note 10 — Stockholders' Equity — Performance Stock Awards for Executive Officers (“Executive PSUs”). Further, in the case of clauses (ii) and (iii), a portion will be surrendered to the Company or sold to cover withholding taxes, depending on how many shares are withheld in these instances, and in the case of clause (iii), the number of shares actually issued will depend on the level of achievement of certain Company-wide targets related to the Company’s operating plan for the fiscal year 2026. The plan expires on September 15, 2027, or upon the earlier completion of all authorized transactions under the plan.

(3)Jeffrey Ford was appointed as the Company's Principal Accounting Officer on June 3, 2026, but was not a Section 16 officer at the time of execution of the listed 10b5-1 Plan, which wasadopted on May 26, 2026. Mr. Ford's plan provides for the potential sale of up to 215,595 shares of the Company's Common Stock, plus any shares awarded under the Company’s 2026 Bonus Program as detailed in Note 10 — Stockholders' Equity — Company-wide Bonus Programs (“Bonus Programs”). However, because certain of Mr. Ford’s planned sale amounts are equal to a designated percentage of the net number of shares resulting from RSUs vesting, of which a portion will be surrendered to the Company or sold to cover withholding taxes, depending on how many shares are withheld in these instances, the maximum number of shares to be sold may be less. The plan expires on October 1, 2028, or upon the earlier completion of all authorized transactions under the plan.

(4) On May 11, 2026, Paula Loop, amember of the Company's Board of Directors, entered into a 10b5-1 Plan, providing for the potential sale of up to 14,664 shares of the Company's Common Stock. The plan expires on May 15, 2027, or upon the earlier completion of all authorized transactions under the plan.

(5) On May 22, 2026, Richard Wong, the Company's Chief Financial Officer, entered into a 10b5-1 Plan, providing for the potential sale of up to 539,216 shares of the Company's Common Stock, plus any shares awarded under the Company’s 2026 Bonus Program as detailed in Note 10 — Stockholders' Equity — Company-wide Bonus Programs (“Bonus Programs”) and a number of shares to be determined that will be purchased under the ESPP. However, because certain of Mr. Wong’s planned sale amounts are equal to a designated percentage of the net number of shares resulting (i) from RSUs vesting or (ii) from the Executive PSUs as detailed in Note 10 — Stockholders' Equity — Performance Stock Awards for Executive Officers (“Executive PSUs”), of which a portion will be surrendered to the Company or sold to cover withholding taxes, depending on how many shares are withheld in these instances, and the level of achievement of certain Company-wide targets related to the Company’s operating plan for the fiscal year 2026 (as it relates to the Executive PSUs), the maximum number of shares to be sold may be less. The plan expires on August 31, 2027, or upon the earlier completion of all authorized transactions under the plan.