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 · 246 ms

HostCertsFirst seenLast seenDNS
grouponmail.ca 21 2026-05-10 2026-09-06 ok
*.grouponmail.ca 21 2026-05-10 2026-09-06 —

Programmatic access, with DNS A records: API GET /v1/hosts/grouponmail.ca (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/grouponmail.ca.