Find every subdomain
of a domain.

Every hostname under a domain that ever appeared in a public TLS certificate — with certificate counts, first/last seen and live DNS status.

6 hosts · 339 ms

HostCertsFirst seenLast seenDNS
microsoftadvertising.com 10 2026-05-06 2026-08-29 ok
c.microsoftadvertising.com 15 2026-02-19 2026-09-23 ok
partnercelebration.microsoftadvertising.com 5 2026-05-18 2026-09-15 ok
arg-glider.microsoftadvertising.com 2 2026-01-12 2026-06-09 ok
www.microsoftadvertising.com 5 2026-05-06 2026-08-28 ok
www.xbox.microsoftadvertising.com 8 2026-05-14 2026-09-09 ok

Programmatic access, with DNS A records: API GET /v1/hosts/microsoftadvertising.com (API key for paging).

Shown here: hostnames with a certificate that is valid now or expired within the last 90 days. The full history since 2013 — hostnames whose last certificate expired earlier — is a Pro plan method: GET /v1/hosts-history/microsoftadvertising.com.