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 · 312 ms

HostCertsFirst seenLast seenDNS
cloud.email.gskmessage.com 1 2025-11-06 2025-11-06 ok
image.email.gskmessage.com 2 2026-02-12 2026-05-13 ok
click.email.gskmessage.com 1 2025-11-06 2025-11-06 ok
view.email.gskmessage.com 1 2025-11-06 2025-11-06 ok

Programmatic access, with DNS A records: API GET /v1/hosts/gskmessage.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/gskmessage.com.