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 · 209 ms

HostCertsFirst seenLast seen
sophos.fr 2 2026-03-19 2026-08-19
secure.sophos.fr 1 2026-02-18 2026-02-18
mta-sts.sophos.fr 5 2026-06-04 2026-10-02
www.sophos.fr 2 2026-03-19 2026-08-19

Programmatic access: API GET /v1/hosts/sophos.fr (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/sophos.fr.