TWILIO INC

Securities Trading Plans of Directors and Executive Officers

During the three months ended September 30, 2026, the following “Rule 10b5-1 trading arrangements” (as defined in Item 408 of Regulation S-K) were adopted or terminated by our directors and officers, each of which was intended to satisfy the affirmative defense in Rule 10b5-1(c):

On September 1, 2026, Aidan Viggiano, our Chief Financial Officer, adopted a Rule 10b5-1 trading plan providing for (i) the sale of shares of our common stock issuable upon the vesting and settlement of 66,760 RSUs outstanding prior to the adoption of the plan, in addition to certain shares Ms. Viggiano acquires upon the vesting and settlement of any RSUs that may be granted after the adoption of the plan, in each case, net of shares sold in mandatory transactions to cover withholding taxes, plus (ii) the sale of up to 58,972 shares at target (or 117,944 shares at maximum, representing the maximum number of shares issuable under the PSUs) of our common stock upon the vesting of performance stock units (“PSUs”), the precise number of shares to vest and settle to be determined based on the Company’s achievement against certain performance conditions, net of shares sold in mandatory transactions to cover withholding taxes. The number of shares listed above for Ms. Viggiano includes shares subject to limit orders that may or may not execute. Trading will not commence under Ms. Viggiano’s new Rule 10b5-1 trading plan until her previous Rule 10b5-1 trading plan terminates by its terms. The duration of the new plan is until September 7, 2027 or earlier if all transactions under the plan have been completed.

No other officers, as defined in Rule 16a-1(f), or directors adopted and/orterminated a “Rule 10b5-1 trading arrangement” or a “non-Rule 10b5-1 trading arrangement,” as defined in Regulation S-K Item 408, during the last fiscal quarter.