Find every subdomain
of a domain.

Every hostname under a domain that ever appeared in a public TLS certificate — with certificate counts and first/last seen dates.

4 hosts · 238 ms

HostCertsFirst seenLast seen
kinsan.co.jp 1 2026-05-22 2026-05-22
www2.kinsan.co.jp 1 2025-11-20 2025-11-20
www3.kinsan.co.jp 1 2026-05-28 2026-05-28
www.kinsan.co.jp 1 2026-05-22 2026-05-22

Programmatic access: API GET /v1/hosts/kinsan.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/kinsan.co.jp.