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.

5 hosts · 258 ms

HostCertsFirst seenLast seen
3nd.it 5 2026-04-29 2026-10-07
email.3nd.it 3 2026-05-08 2026-08-28
tmail.3nd.it 3 2026-05-08 2026-08-28
mta-sts.3nd.it 3 2026-05-31 2026-08-22
www.3nd.it 5 2026-04-29 2026-10-07

Programmatic access: API GET /v1/hosts/3nd.it (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/3nd.it.