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.

7 hosts · 365 ms

HostCertsFirst seenLast seenDNS
peninsula-ca.com 30 2026-04-27 2026-09-06 ok
*.peninsula-ca.com 18 2026-05-06 2026-09-01 —
reach360.peninsula-ca.com 5 2026-04-28 2026-08-28 ok
call-tracking.peninsula-ca.com 12 2026-04-27 2026-09-06 ok
*.call-tracking.peninsula-ca.com 12 2026-04-27 2026-09-06 —
billing.peninsula-ca.com 4 2026-02-13 2026-09-27 ok
bimi.peninsula-ca.com 2 2026-09-29 2026-09-29 ok

Programmatic access, with DNS A records: API GET /v1/hosts/peninsula-ca.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/peninsula-ca.com.