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 · 334 ms

HostCertsFirst seenLast seenDNS
cloud.email.specs.com 3 2026-06-01 2026-06-01 ok
image.email.specs.com 40 2026-05-26 2026-06-25 ok
click.email.specs.com 2 2026-06-01 2026-06-01 ok
view.email.specs.com 3 2026-06-01 2026-06-01 ok

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