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.

5 hosts · 269 ms

HostCertsFirst seenLast seenDNS
coastal.us 7 2026-04-26 2026-08-23 ok
*.coastal.us 7 2026-04-26 2026-08-23 —
go.coastal.us 12 2026-04-23 2026-09-20 ok
events.coastal.us 4 2026-04-16 2026-08-14 ok
www.coastal.us 14 2026-05-05 2026-08-31 ok

Programmatic access, with DNS A records: API GET /v1/hosts/coastal.us (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/coastal.us.