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.

3 hosts · 226 ms

HostCertsFirst seenLast seenDNS
tsubakimoto.tw 4 2026-06-01 2026-10-03 ok
staging.tsubakimoto.tw 3 2026-04-19 2026-08-21 ok
www.tsubakimoto.tw 4 2026-06-01 2026-10-03 ok

Programmatic access, with DNS A records: API GET /v1/hosts/tsubakimoto.tw (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/tsubakimoto.tw.