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.

9 hosts · 257 ms

HostCertsFirst seenLast seenDNS
naito-sec.co.jp 3 2025-10-27 2026-04-28 ok
test-web.naito-sec.co.jp 6 2026-02-24 2026-08-20 ok
renew-web.naito-sec.co.jp 1 2026-02-25 2026-02-25 nxdomain
mng-admin.naito-sec.co.jp 2 2026-02-25 2026-07-28 ok
test-mng-admin.naito-sec.co.jp 3 2026-02-25 2026-07-28 ok
info.naito-sec.co.jp 1 2026-06-16 2026-06-16 ok
succe-s.naito-sec.co.jp 6 2026-06-16 2026-06-16 ok
account.naito-sec.co.jp 1 2026-06-16 2026-06-16 ok
www.naito-sec.co.jp 3 2025-10-27 2026-04-28 ok

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