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.

6 hosts · 534 ms

HostCertsFirst seenLast seenDNS
breethe.com 2 2025-07-10 2026-06-09 ok
*.breethe.com 2 2025-07-10 2026-06-09 —
click.breethe.com 18 2026-05-30 2026-09-26 ok
main.breethe.com 8 2026-05-02 2026-08-28 ok
sleep.breethe.com 10 2026-04-17 2026-08-13 ok
quiz.breethe.com 6 2026-05-17 2026-09-12 ok

Programmatic access, with DNS A records: API GET /v1/hosts/breethe.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/breethe.com.