Find every subdomain
of a domain.

Every hostname under a domain that ever appeared in a public TLS certificate — with certificate counts and first/last seen dates.

4 hosts · 228 ms

HostCertsFirst seenLast seen
reserve.ne.jp 28 2026-04-08 2026-10-07
*.reserve.ne.jp 16 2026-04-08 2026-10-06
sys-nfc-reader.reserve.ne.jp 2 2026-02-20 2026-07-23
sys-node-aws.reserve.ne.jp 1 2025-11-24 2025-11-24

Programmatic access: API GET /v1/hosts/reserve.ne.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/reserve.ne.jp.