X0609 4 2026-09-21 0 0001561550 Datadog, Inc. DDOG 0001120741 OBSTLER DAVID M false C/O DATADOG, INC. 620 8TH AVENUE, 45TH FLOOR NEW YORK NY 10018 0 1 0 0 Chief Financial Officer 1 Class A Common Stock 2026-09-21 4 S 0 10000 241.25 D 368067 D Class A Common Stock 2026-09-21 4 C 0 3000 0 A 3000 I By Trust Class A Common Stock 2026-09-21 4 S 0 3000 241.25 D 0 I By Trust Class A Common Stock 2026-09-21 4 C 0 3000 0 A 3000 I By Trust Class A Common Stock 2026-09-21 4 S 0 3000 241.25 D 0 I By Trust Class B Common Stock 2026-09-21 4 C 0 3000 0 D Class A Common Stock 3000 31198 I By Trust Class B Common Stock 2026-09-21 4 C 0 3000 0 D Class A Common Stock 3000 31199 I By Trust Class B Common Stock Class A Common Stock 8103 8103 D Shares sold pursuant to a 10b5-1 plan dated June 13, 2026. Each share of Class B Common Stock is convertible at any time at the option of the Reporting Person into one share of Class A Common Stock and has no expiration date. Each share of Class B Common Stock will convert automatically into one share of Class A Common Stock upon the earliest of: (i) any transfer, whether or not for value, except for certain "Permitted Transfers" as defined in the Issuer's amended and restated certificate of incorporation, (ii) the death of the Reporting Person in the case of shares held directly or in a trustee capacity, and (iii) the tenth anniversary of the Issuer's initial public offering of its Class A Common Stock. Shares are held directly by Obstler Children 2019 Trust FBO the Reporting Person's other child, of which the Reporting Person's spouse is Trustee. See Footnote 4. Shares are held directly by Obstler Children 2019 Trust FBO the Reporting Person's child, of which the Reporting Person's spouse is Trustee. Obstler Children 2019 Trust FBO the Reporting Person's child and Obstler Children 2019 Trust FBO the Reporting Person's other child are separate trusts for the benefit of the Reporting Person's children with substantially identical terms. /s/ Kerry Acocella, Attorney-in-Fact 2026-09-23