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 · 216 ms

HostCertsFirst seenLast seenDNS
premiumwater-hd.co.jp 9 2026-01-13 2026-08-09 ok
staging.premiumwater-hd.co.jp 5 2026-05-20 2026-09-17 ok
pt.premiumwater-hd.co.jp 3 2026-05-07 2026-08-25 ok
skygw.premiumwater-hd.co.jp 7 2026-05-15 2026-09-04 ok
www.premiumwater-hd.co.jp 1 2026-01-13 2026-01-13 ok

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