X0306 4 2020-06-11 0 0001561550 Datadog, Inc. DDOG 0001784030 Callahan Michael James C/O DATADOG, INC. 620 8TH AVENUE, 45TH FLOOR NEW YORK NY 10018 1 0 0 0 Class A Common Stock 2020-06-11 4 A 0 2301 0.00 A 5959 D Class A Common Stock 20000 I By GRAT Represents the number of shares underlying Restricted Stock Units ("RSUs") granted pursuant to the Issuer's non-employee director compensation policy. Each RSU represents a contingent right to receive one share of Issuer's Class A common stock. The RSUs vest on the earlier of (A) the Company's next annual meeting of stockholders and (B) June 11, 2021, in each case, subject to the Reporting Person's continuous service to the Issuer through the vesting date. Shares are held directly by The Michael Callahan Grantor Retained Annuity Trust, of which Reporting Person is Trustee. Michael Callahan, by /s/ Ron A. Metzger, Attorney-in-Fact 2020-06-15