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.

5 hosts · 293 ms

HostCertsFirst seenLast seenDNS
crdn.com 1 2026-05-15 2026-05-15 ok
*.crdn.com 17 2026-05-12 2026-09-06 —
hub.crdn.com 1 2026-08-01 2026-08-01 ok
help.crdn.com 9 2026-06-15 2026-09-23 ok
support.crdn.com 6 2026-06-24 2026-10-01 ok

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