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.

2 hosts · 216 ms

HostCertsFirst seenLast seen
ssl.cr 66 2026-02-13 2026-09-29
www.ssl.cr 72 2025-08-14 2026-10-01

Programmatic access: API GET /v1/hosts/ssl.cr (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/ssl.cr.