X0306 4 2017-08-15 0001447669 TWILIO INC TWLO 0001184753 DALZELL RICHARD L C/O TWILIO INC. 375 BEALE STREET, SUITE 300 SAN FRANCISCO CA 94105 1 Class A Common Stock 2017-08-15 4 C 0 2500 0 A 8505 D Class A Common Stock 2017-08-15 4 S 0 2500 31.177 D 6005 D Employee Stock Option (right to buy) 3.86 2017-08-15 4 M 0 2500 0 D 2024-03-24 Class B Common Stock 2500 142500 D Class B Common Stock 2017-08-15 4 M 0 2500 0 A Class A Common Stock 2500 2500 D Class B Common Stock 2017-08-15 4 C 0 2500 0 D Class A Common Stock 2500 0 D A portion of these shares represent Restricted Stock Units ("RSUs"). Each RSU represents the contingent right to receive one share of the Issuer's Class A common stock. 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 $30.82 to $31.47 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. The shares subject to the option are fully vested and exercisable by the reporting person. 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. /s/ Mariam Sattar as attorney in fact for Reporting Person 2017-08-17