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 · 302 ms

HostCertsFirst seenLast seenDNS
atlasapitraining.com 14 2025-10-13 2026-09-30 ok
*.atlasapitraining.com 14 2025-10-13 2026-09-30 —
email.atlasapitraining.com 3 2026-05-27 2026-08-21 ok
www.atlasapitraining.com 4 2026-04-13 2026-08-11 ok

Programmatic access, with DNS A records: API GET /v1/hosts/atlasapitraining.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/atlasapitraining.com.