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.

2 hosts · 261 ms

HostCertsFirst seenLast seenDNS
usci.edu 6 2026-05-08 2026-09-03 nodata
*.usci.edu 6 2026-05-08 2026-09-03 —

Programmatic access, with DNS A records: API GET /v1/hosts/usci.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/usci.edu.