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 · 381 ms

HostCertsFirst seenLast seenDNS
westbrookeassociates.com 3 2026-01-09 2026-05-23 ok
email.westbrookeassociates.com 3 2026-04-22 2026-10-06 ok
www.email.westbrookeassociates.com 3 2026-04-22 2026-10-06 nxdomain
www.westbrookeassociates.com 3 2026-01-09 2026-05-23 ok

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