Find every subdomain
of a domain.

Every hostname under a domain that ever appeared in a public TLS certificate — with certificate counts and first/last seen dates.

4 hosts · 223 ms

HostCertsFirst seenLast seen
image.email.ucas.com 4 2025-12-08 2026-09-21
click.email.ucas.com 2 2025-10-02 2026-09-19
pages.email.ucas.com 3 2025-10-08 2026-09-25
view.email.ucas.com 2 2025-10-02 2026-09-19

Programmatic access: API GET /v1/hosts/email.ucas.com (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/email.ucas.com.