Find every subdomain
of a domain.

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

4 hosts · 373 ms

HostCertsFirst seenLast seen
starfish.com 16 2026-04-25 2026-08-26
*.starfish.com 16 2026-04-25 2026-08-26
my-account.starfish.com 4 2026-04-19 2026-08-17
checkout.starfish.com 5 2026-04-24 2026-08-22

Programmatic access: API GET /v1/hosts/starfish.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/starfish.com.