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 · 292 ms

HostCertsFirst seenLast seen
hekishin.jp 1 2026-02-27 2026-02-27
*.hekishin.jp 4 2025-10-21 2026-09-22
faq.hekishin.jp 14 2026-06-06 2026-10-02
www.hekishin.jp 1 2026-02-27 2026-02-27

Programmatic access: API GET /v1/hosts/hekishin.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/hekishin.jp.