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.

3 hosts · 324 ms

HostCertsFirst seenLast seen
resurs.dk 2 2026-03-25 2026-08-25
*.resurs.dk 2 2026-03-25 2026-08-25
www.resurs.dk 4 2025-07-30 2026-08-25

Programmatic access: API GET /v1/hosts/resurs.dk (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/resurs.dk.