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 · 249 ms

HostCertsFirst seenLast seenDNS
radix.email 21 2026-04-13 2026-10-07 ok
*.radix.email 12 2026-04-13 2026-10-07 —
mt-link.radix.email 1 2026-08-26 2026-08-26 ok
www.radix.email 9 2026-04-21 2026-09-21 ok

Programmatic access, with DNS A records: API GET /v1/hosts/radix.email (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/radix.email.