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.

10 hosts · 218 ms

HostCertsFirst seenLast seen
ra.co 12 2025-11-07 2026-09-21
*.ra.co 12 2025-11-07 2026-09-21
1000.ra.co 6 2026-06-02 2026-10-02
afacbe60044d41c7b1b29d1889e8c2d8.ra.co 2 2026-04-12 2026-09-12
*.afacbe60044d41c7b1b29d1889e8c2d8.ra.co 2 2026-04-12 2026-09-12
store.ra.co 5 2026-05-10 2026-09-06
l.ra.co 5 2026-06-12 2026-10-09
pro.ra.co 11 2026-05-19 2026-09-15
group.ra.co 12 2026-04-30 2026-06-28
support.ra.co 5 2026-05-17 2026-09-13

Programmatic access: API GET /v1/hosts/ra.co (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/ra.co.