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.

1 host · 231 ms

HostCertsFirst seenLast seenDNS
login.studentaid.gov 4 2025-08-29 2026-08-25 ok

Programmatic access, with DNS A records: API GET /v1/hosts/login.studentaid.gov (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/login.studentaid.gov.