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.

1 host · 268 ms

HostCertsFirst seenLast seenDNS
newsletters.cbc.ca 3 2025-11-05 2026-08-27 ok

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