X0306 4 2017-05-18 0001447669 TWILIO INC TWLO 0001665730 Smith Karyn C/O TWILIO INC. 375 BEALE STREET, SUITE 300 SAN FRANCISCO CA 94105 1 General Counsel and Secretary Class A Common Stock 2017-05-18 4 C 0 5213 0 A 5213 I By The Karyn Smith Revocable Trust Class A Common Stock 2017-05-18 4 S 0 5213 24.594 D 0 I By The Karyn Smith Revocable Trust Class A Common Stock 1750 D Class B Common Stock 2017-05-18 4 C 0 5213 0 D Class A Common Stock 5213 3461 I By The Karyn Smith Revocable Trust Class B Common Stock Class A Common Stock 20672 20672 D The Karyn Smith Revocable Trust U/A/D 9/15/06 Amended 12/23/11, Karyn Smith Trustee. The sales reported were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person. The reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $24.12 to $25.01 per share, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or to 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. Includes 1,750 shares acquired by the reporting person on May 15, 2017, pursuant to the Issuer's 2016 Employee Stock Purchase Plan. Each share of Class B common stock is convertible into one share of Class A common stock at the option of the holder and has no expiration date. A portion of these shares represent Restricted Stock Units ("RSUs"). Each RSU represents a contingent right to receive one share of the Issuer's Class B common stock. /s/ Mariam Sattar as attorney in fact for Reporting Person 2017-05-22