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.

12 hosts · 321 ms

HostCertsFirst seenLast seenDNS
oo2.fr 9 2026-04-21 2026-09-21 ok
gestof.oo2.fr 5 2026-05-30 2026-09-27 ok
img.mail.oo2.fr 6 2026-04-21 2026-08-17 ok
r.mail.oo2.fr 4 2026-05-12 2026-07-31 ok
img.nl.oo2.fr 8 2026-05-07 2026-09-02 ok
r.nl.oo2.fr 3 2026-06-17 2026-09-05 ok
go.oo2.fr 5 2026-05-24 2026-09-21 ok
labs.oo2.fr 5 2026-05-29 2026-09-26 ok
factures.oo2.fr 4 2026-04-29 2026-07-15 ok
forms.oo2.fr 156 2026-05-06 2026-10-06 ok
mta-sts.oo2.fr 4 2026-04-21 2026-08-20 ok
www.oo2.fr 5 2026-05-24 2026-09-21 ok

Programmatic access, with DNS A records: API GET /v1/hosts/oo2.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/oo2.fr.