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.

4 hosts · 326 ms

HostCertsFirst seenLast seenDNS
admissions.msstate.edu 2 2025-07-09 2026-06-25 ok
www2.admissions.msstate.edu 2 2025-07-09 2026-06-25 ok
discover.admissions.msstate.edu 16 2026-05-07 2026-09-03 ok
www.admissions.msstate.edu 2 2025-07-09 2026-06-25 ok

Programmatic access, with DNS A records: API GET /v1/hosts/admissions.msstate.edu (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/admissions.msstate.edu.