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.

6 hosts · 213 ms

HostCertsFirst seenLast seenDNS
ca.newsletters.yahoo.net 5 2026-02-03 2026-09-28 ok
e.newsletters.yahoo.net 5 2026-02-03 2026-09-28 ok
subscription.newsletters.yahoo.net 10 2026-04-21 2026-08-17 ok
preferences.newsletters.yahoo.net 10 2026-05-31 2026-09-26 ok
images.newsletters.yahoo.net 4 2026-02-03 2026-09-28 ok
view.newsletters.yahoo.net 4 2026-02-03 2026-09-28 ok

Programmatic access, with DNS A records: API GET /v1/hosts/newsletters.yahoo.net (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.yahoo.net.