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 · 264 ms

HostCertsFirst seenLast seenDNS
dmarc25.jp 3 2025-10-06 2026-10-05 ok
*.dmarc25.jp 3 2025-10-06 2026-10-05 —
reporter-test-i1-mx.dmarc25.jp 5 2026-05-15 2026-09-19 ok

Programmatic access, with DNS A records: API GET /v1/hosts/dmarc25.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/dmarc25.jp.