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 · 197 ms

HostCertsFirst seenLast seenDNS
cloud.contact.promise.co.jp 1 2026-05-22 2026-05-22 ok
image.contact.promise.co.jp 4 2025-07-12 2026-09-01 ok
click.contact.promise.co.jp 1 2026-05-23 2026-05-23 ok
view.contact.promise.co.jp 2 2025-07-06 2026-06-24 ok

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