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 · 255 ms

HostCertsFirst seenLast seen
b-sec.gmbh 15 2026-04-22 2026-09-23
*.b-sec.gmbh 8 2026-05-27 2026-09-23
mta-sts.b-sec.gmbh 7 2026-04-22 2026-08-18
*.mta-sts.b-sec.gmbh 7 2026-04-22 2026-08-18

Programmatic access: API GET /v1/hosts/b-sec.gmbh (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/b-sec.gmbh.