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 · 194 ms

HostCertsFirst seenLast seenDNS
lightfx.jp 4 2025-06-09 2026-06-23 ok
*.lightfx.jp 6 2025-06-09 2026-09-01 —
help.lightfx.jp 16 2026-05-07 2026-09-02 ok

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