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.

7 hosts · 280 ms

HostCertsFirst seenLast seenDNS
hellosunset.com 28 2026-04-13 2026-09-07 ok
*.hellosunset.com 14 2026-04-13 2026-09-07 —
ph.hellosunset.com 6 2026-06-03 2026-10-01 ok
api.hellosunset.com 5 2026-05-12 2026-09-14 ok
learn.hellosunset.com 4 2026-05-25 2026-07-23 ok
trust.hellosunset.com 2 2026-08-13 2026-08-13 ok
www.hellosunset.com 10 2026-05-11 2026-09-07 ok

Programmatic access, with DNS A records: API GET /v1/hosts/hellosunset.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/hellosunset.com.