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.

4 hosts · 253 ms

HostCertsFirst seenLast seenDNS
horiuchi-color.co.jp 11 2025-11-20 2026-09-16 ok
*.horiuchi-color.co.jp 10 2025-11-27 2026-09-16 —
mta-sts.horiuchi-color.co.jp 4 2026-05-13 2026-10-02 ok
www.horiuchi-color.co.jp 1 2025-11-20 2025-11-20 ok

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