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.

4 hosts · 358 ms

HostCertsFirst seenLast seenDNS
ursamajor.com 16 2026-05-06 2026-09-09 ok
*.ursamajor.com 6 2026-05-14 2026-09-09 —
shop.ursamajor.com 17 2026-04-11 2026-09-23 ok
www.ursamajor.com 8 2026-05-10 2026-09-05 ok

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