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 · 224 ms

HostCertsFirst seenLast seenDNS
entry-test.hksl.co.jp 125 2025-06-30 2026-09-28 ok
www.hksl.co.jp 125 2025-06-30 2026-09-28 ok
entry.hksl.co.jp 125 2025-06-30 2026-09-28 ok

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