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 · 301 ms

HostCertsFirst seenLast seenDNS
rhi.net 2 2025-10-29 2026-09-28 ok
*.rhi.net 2 2025-10-29 2026-09-28 —
autodiscover.rhi.net 2 2025-11-12 2026-07-17 ok

Programmatic access, with DNS A records: API GET /v1/hosts/rhi.net (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/rhi.net.