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 · 282 ms

HostCertsFirst seenLast seen
cobi-biobank.de 5 2026-05-16 2026-09-13
cobichecker.cobi-biobank.de 5 2026-04-28 2026-08-27
www.cobi-biobank.de 5 2026-05-16 2026-09-13

Programmatic access: API GET /v1/hosts/cobi-biobank.de (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/cobi-biobank.de.