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.

9 hosts · 225 ms

HostCertsFirst seenLast seen
fernes.com 6 2026-04-21 2026-08-31
trk.send.fernes.com 11 2026-05-25 2026-09-20
osmee.fernes.com 13 2026-05-28 2026-09-23
api.fernes.com 2 2026-05-17 2026-05-17
mta-sts.fernes.com 3 2026-04-28 2026-09-18
account.fernes.com 13 2026-04-21 2026-08-19
www.fernes.com 9 2026-04-21 2026-08-30
story.fernes.com 7 2026-06-13 2026-09-21
try.fernes.com 3 2026-04-20 2026-07-19

Programmatic access: API GET /v1/hosts/fernes.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/fernes.com.