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 · 331 ms

HostCertsFirst seenLast seenDNS
ursamajor.us 7 2026-05-17 2026-09-19 ok
*.ursamajor.us 7 2026-05-17 2026-09-19 —
github.azva.ursamajor.us 1 2025-11-21 2025-11-21 nxdomain
www.github.azva.ursamajor.us 1 2025-11-21 2025-11-21 nxdomain

Programmatic access, with DNS A records: API GET /v1/hosts/ursamajor.us (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/ursamajor.us.