Find every subdomain
of a domain.

Every hostname under a domain that ever appeared in a public TLS certificate — with certificate counts, first/last seen and live DNS status.

3 hosts · 305 ms

HostCertsFirst seenLast seenDNS
csps.cz 1 2026-02-17 2026-02-17 ok
sgtm.csps.cz 5 2026-04-18 2026-09-27 ok
www.csps.cz 1 2026-02-17 2026-02-17 ok

Programmatic access, with DNS A records: API GET /v1/hosts/csps.cz (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/csps.cz.