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.

7 hosts · 207 ms

HostCertsFirst seenLast seenDNS
gate1email.com 2 2026-02-06 2026-02-16 ok
i.gate1email.com 8 2026-04-17 2026-08-13 ok
l.gate1email.com 12 2026-02-06 2026-08-16 ok
s.gate1email.com 10 2026-05-08 2026-09-04 ok
w.gate1email.com 10 2026-04-28 2026-08-24 ok
www.gate1email.com 2 2026-02-06 2026-02-16 nxdomain
x.gate1email.com 8 2026-05-22 2026-09-17 ok

Programmatic access, with DNS A records: API GET /v1/hosts/gate1email.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/gate1email.com.