Find every subdomain
of a domain.

Every hostname under a domain that ever appeared in a public TLS certificate — with certificate counts and first/last seen dates.

4 hosts · 265 ms

HostCertsFirst seenLast seen
key.email 8 2026-04-23 2026-09-03
*.key.email 8 2026-04-23 2026-09-03
track.key.email 3 2026-09-30 2026-09-30
trackdev.key.email 2 2026-09-28 2026-09-28

Programmatic access: API GET /v1/hosts/key.email (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/key.email.