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.

5 hosts · 294 ms

HostCertsFirst seenLast seen
gsystems.de 3 2025-12-11 2026-01-20
*.gsystems.de 3 2025-12-11 2026-01-20
newsletter.gsystems.de 3 2026-05-20 2026-08-04
mta-sts.gsystems.de 5 2026-05-10 2026-09-10
www.gsystems.de 1 2026-01-20 2026-01-20

Programmatic access: API GET /v1/hosts/gsystems.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/gsystems.de.