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.

5 hosts · 330 ms

HostCertsFirst seenLast seenDNS
newsletters.aol.com 1 2026-04-20 2026-04-20 nodata
ca.newsletters.aol.com 1 2026-04-27 2026-04-27 ok
e.newsletters.aol.com 6 2026-04-27 2026-08-20 ok
images.newsletters.aol.com 1 2026-04-27 2026-04-27 ok
view.newsletters.aol.com 1 2026-04-27 2026-04-27 ok

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