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 · 297 ms

HostCertsFirst seenLast seenDNS
thunderbay5050.ca 2 2025-07-16 2026-07-17 ok
mail.thunderbay5050.ca 5 2026-05-18 2026-09-13 ok
www.thunderbay5050.ca 2 2025-07-16 2026-07-17 ok

Programmatic access, with DNS A records: API GET /v1/hosts/thunderbay5050.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/thunderbay5050.ca.