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.

11 hosts · 355 ms

HostCertsFirst seenLast seenDNS
cnt.us 10 2026-05-02 2026-08-28 ok
rscloud.cnt.us 5 2026-04-27 2026-08-26 ok
salesforce.cnt.us 3 2026-06-02 2026-08-31 ok
trading.cnt.us 5 2026-05-14 2026-09-12 ok
application.cnt.us 3 2026-06-02 2026-08-31 ok
voyager.cnt.us 3 2026-06-02 2026-08-31 ok
applications.cnt.us 16 2026-05-04 2026-08-30 ok
appointments.cnt.us 3 2026-06-02 2026-08-31 ok
mta-sts.cnt.us 1 2026-01-07 2026-01-07 ok
test.cnt.us 2 2026-06-02 2026-06-02 ok
www.cnt.us 20 2026-04-30 2026-08-26 ok

Programmatic access, with DNS A records: API GET /v1/hosts/cnt.us (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/cnt.us.