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.

24 hosts · 337 ms

HostCertsFirst seenLast seenDNS
classcloud.ai 14 2026-01-21 2026-09-11 ok
*.classcloud.ai 3 2026-01-21 2026-07-23 —
beta.classcloud.ai 12 2026-04-10 2026-09-11 ok
public.classcloud.ai 1 2026-01-26 2026-01-26 ok
auth.classcloud.ai 9 2026-05-31 2026-09-26 ok
api.classcloud.ai 2 2026-02-20 2026-07-23 nxdomain
*.api.classcloud.ai 2 2026-02-20 2026-07-23 —
email.classcloud.ai 1 2026-01-21 2026-01-21 nxdomain
*.email.classcloud.ai 1 2026-01-21 2026-01-21 —
login.classcloud.ai 9 2026-05-31 2026-09-26 ok
admin.classcloud.ai 11 2026-05-31 2026-09-27 ok
help.classcloud.ai 4 2026-04-15 2026-08-15 ok
*.app.classcloud.ai 2 2026-02-20 2026-07-23 —
newsletter.classcloud.ai 11 2026-01-21 2026-08-15 ok
*.newsletter.classcloud.ai 1 2026-01-21 2026-01-21 —
elinkb84.newsletter.classcloud.ai 10 2026-04-18 2026-08-14 ok
partners.classcloud.ai 7 2026-05-03 2026-09-05 ok
auth.partners.classcloud.ai 6 2026-05-03 2026-08-29 ok
email.partners.classcloud.ai 4 2026-05-06 2026-08-24 ok
login.partners.classcloud.ai 6 2026-05-03 2026-08-29 ok
status.classcloud.ai 1 2026-08-11 2026-08-11 ok
trust.classcloud.ai 4 2026-04-17 2026-08-15 ok
www.classcloud.ai 11 2026-03-06 2026-09-10 ok
policy.classcloud.ai 1 2026-05-18 2026-05-18 ok

Programmatic access, with DNS A records: API GET /v1/hosts/classcloud.ai (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/classcloud.ai.