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.

7 hosts · 363 ms

HostCertsFirst seenLast seenDNS
graymatter-robotics.com 5 2026-05-10 2026-09-10 ok
research.graymatter-robotics.com 1 2026-10-05 2026-10-05 ok
atlas.graymatter-robotics.com 1 2026-08-26 2026-08-26 ok
hello-test.graymatter-robotics.com 1 2026-01-13 2026-01-13 nodata
www.graymatter-robotics.com 5 2026-05-10 2026-09-10 ok
snx.graymatter-robotics.com 1 2026-01-14 2026-01-14 ok
factory.graymatter-robotics.com 3 2026-06-07 2026-08-07 ok

Programmatic access, with DNS A records: API GET /v1/hosts/graymatter-robotics.com (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/graymatter-robotics.com.