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.

3 hosts · 302 ms

HostCertsFirst seenLast seenDNS
insight.gmo 6 2025-11-25 2026-10-01 ok
*.insight.gmo 5 2026-04-24 2026-10-01 —
www.insight.gmo 16 2025-11-25 2026-10-01 ok

Programmatic access, with DNS A records: API GET /v1/hosts/insight.gmo (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/insight.gmo.