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.

5 hosts · 274 ms

HostCertsFirst seenLast seenDNS
ntsinc.co.jp 2 2026-06-19 2026-09-01 ok
*.ntsinc.co.jp 2 2026-06-19 2026-09-01 —
mg.ntsinc.co.jp 2 2026-05-26 2026-08-11 ok
desk.ntsinc.co.jp 2 2026-05-07 2026-07-24 ok
mail.ntsinc.co.jp 2 2026-05-05 2026-07-22 ok

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