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.

3 hosts · 280 ms

HostCertsFirst seenLast seenDNS
sunsets.com 3 2026-02-11 2026-07-09 ok
returns.sunsets.com 9 2026-06-01 2026-09-27 ok
www.sunsets.com 3 2026-02-11 2026-07-10 ok

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