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.

10 hosts · 318 ms

HostCertsFirst seenLast seenDNS
thewatchkeepers.com 12 2026-05-07 2026-09-03 ok
*.thewatchkeepers.com 12 2026-05-07 2026-09-03 —
perf-tests-southeast-asia.thewatchkeepers.com 2 2026-03-26 2026-03-26 ok
cdn-cpo-qual.thewatchkeepers.com 8 2026-04-24 2026-08-20 ok
cdn-cpo.thewatchkeepers.com 10 2026-04-24 2026-08-20 ok
perf-tests.thewatchkeepers.com 3 2026-03-24 2026-03-27 ok
perf-tests-us.thewatchkeepers.com 1 2026-03-25 2026-03-25 ok
cdn-cpo-test.thewatchkeepers.com 8 2026-04-24 2026-08-20 ok
auth0-dev.thewatchkeepers.com 2 2026-04-16 2026-04-16 nxdomain
cdn-cpo-dev.thewatchkeepers.com 8 2026-04-22 2026-08-18 ok

Programmatic access, with DNS A records: API GET /v1/hosts/thewatchkeepers.com (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/thewatchkeepers.com.