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.

2 hosts · 298 ms

HostCertsFirst seenLast seenDNS
natp.natptax.org 4 2025-07-12 2026-06-12 ok
natp-test.natptax.org 1 2026-08-31 2026-08-31 —

Programmatic access, with DNS A records: API GET /v1/hosts/natptax.org (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/natptax.org.