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 · 219 ms

HostCertsFirst seenLast seenDNS
mnb.resona-hd.co.jp 1 2026-01-16 2026-01-16 nodata
csirt.test.resona-hd.co.jp 5 2026-05-29 2026-09-26 ok

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