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.

14 hosts · 264 ms

HostCertsFirst seenLast seenDNS
rheos.jp 1 2025-12-11 2025-12-11 nodata
*.rheos.jp 2 2025-12-11 2025-12-11 —
123.rheos.jp 4 2025-10-08 2026-07-15 ok
a8.123.rheos.jp 7 2026-05-18 2026-09-15 ok
hifumi.rheos.jp 4 2025-10-08 2026-07-15 ok
events-hifumi.rheos.jp 2 2025-10-07 2026-09-07 ok
lp.hifumi.rheos.jp 7 2026-04-27 2026-10-02 ok
contents.hifumi.rheos.jp 3 2026-05-29 2026-09-12 ok
sbirheoshifumi.rheos.jp 1 2025-12-19 2025-12-19 nodata
*.sbirheoshifumi.rheos.jp 1 2025-12-19 2025-12-19 —
www.sbirheoshifumi.rheos.jp 2 2025-09-08 2025-09-08 ok
labo.rheos.jp 3 2026-04-21 2026-08-14 ok
aws-genu.rheos.jp 2 2025-06-27 2026-05-28 ok
www.rheos.jp 5 2025-10-08 2026-07-15 ok

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