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 · 297 ms

HostCertsFirst seenLast seenDNS
threebestrated.ca 18 2025-07-30 2026-08-19 ok
*.threebestrated.ca 12 2026-04-23 2026-08-19 —
mail.threebestrated.ca 5 2026-05-11 2026-09-10 ok
www.threebestrated.ca 6 2025-07-30 2026-08-06 ok

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