144 0001783882 XXXXXXXX LIVE 0001561550 Datadog, Inc. 001-39051 620 8th Avenue, 45th Floor New York NY 10018 8663294466 2019 SHAH FAMILY TRUST Director Class A Common Morgan Stanley Smith Barney LLC Executive Financial Services

1 New York Plaza 8th Floor New York NY 10004

7916 1256585.84 323270704 10/13/2025 NASDAQ Common 11/06/2012 Fund distribution Affiliates of Index Venture Associates N 7916 11/06/2012 Fund distribution N 10b5-1 Sales for 2019 SHAH FAMILY TRUST

620 8th Avenue, 45th Floor New York NY 10018

Class A Common 09/12/2025 7916 1090672.81 10b5-1 Sales for 2019 SHAH FAMILY TRUST

620 8th Avenue, 45th Floor New York NY 10018

Class A Common 07/15/2025 7924 1115703.16 The securities to be sold were acquired upon a pro-rata distribution of a fund during the period of 11/6/2012 through 5/8/2019. Sales that were executed on October 13, 2025 are being reported on this Form 144 filed on October 14, 2025 given the EDGAR system was not accepting filings on October 13, 2025 in observance of the federal holiday. 10/13/2025 06/13/2025 /s/ Shardul Gautam Shah