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 · 326 ms

HostCertsFirst seenLast seenDNS
cloud.email2.tsc.ca 4 2026-03-02 2026-08-04 ok
image.email2.tsc.ca 4 2026-03-31 2026-09-28 ok
click.email2.tsc.ca 4 2026-03-02 2026-08-04 ok
view.email2.tsc.ca 3 2026-03-02 2026-08-04 ok

Programmatic access, with DNS A records: API GET /v1/hosts/email2.tsc.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/email2.tsc.ca.