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 · 229 ms

HostCertsFirst seenLast seen
udb.at 10 2026-05-09 2026-09-07
webudb.udb.at 3 2026-05-11 2026-08-04
www.udb.at 9 2026-05-09 2026-10-08

Programmatic access: API GET /v1/hosts/udb.at (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/udb.at.