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.

2 hosts · 180 ms

HostCertsFirst seenLast seenDNS
xwww.test.resona-ream.co.jp 5 2026-06-08 2026-09-25 ok
www.resona-ream.co.jp 21 2025-09-02 2026-08-20 ok

Programmatic access, with DNS A records: API GET /v1/hosts/resona-ream.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/resona-ream.co.jp.