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 · 346 ms

HostCertsFirst seenLast seenDNS
usaatest.com 5 2026-04-02 2026-09-17 ok
edge.usaatest.com 1 2026-02-12 2026-02-12 ok
sp-onedrive-api-exo-azure.usaatest.com 1 2026-09-04 2026-09-04 nxdomain
sharepoint-api-exo-azure.usaatest.com 5 2026-08-27 2026-09-01 nxdomain
hawk.usaatest.com 1 2026-02-12 2026-02-12 nodata
webmail.usaatest.com 2 2025-10-24 2026-02-12 ok
autodiscover.usaatest.com 2 2025-10-24 2026-02-12 ok

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