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.

3 hosts · 207 ms

HostCertsFirst seenLast seenDNS
engine-f.co.jp 1 2026-01-13 2026-01-13 ok
mail.engine-f.co.jp 4 2026-04-30 2026-07-21 ok
www.engine-f.co.jp 1 2026-01-13 2026-01-13 ok

Programmatic access, with DNS A records: API GET /v1/hosts/engine-f.co.jp (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/engine-f.co.jp.