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.

6 hosts · 218 ms

HostCertsFirst seenLast seen
rarebird.coffee 17 2026-05-28 2026-10-07
help.rarebird.coffee 10 2026-05-19 2026-09-15
sms.rarebird.coffee 13 2026-05-28 2026-09-23
account.rarebird.coffee 15 2026-05-15 2026-09-25
www.rarebird.coffee 16 2026-05-28 2026-10-07
try.rarebird.coffee 8 2026-05-15 2026-09-10

Programmatic access: API GET /v1/hosts/rarebird.coffee (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/rarebird.coffee.