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 · 257 ms

HostCertsFirst seenLast seenDNS
theaddisonwest.com 12 2026-05-20 2026-09-28 ok
account.theaddisonwest.com 18 2026-05-18 2026-09-27 ok
www.theaddisonwest.com 17 2026-05-20 2026-09-30 ok

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