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.

13 hosts · 250 ms

HostCertsFirst seenLast seenDNS
coloradotech.edu 25 2026-02-10 2026-10-05 ok
*.coloradotech.edu 25 2026-02-10 2026-10-05 —
int-discussionboard.coloradotech.edu 14 2026-07-15 2026-09-30 nxdomain
presentation.coloradotech.edu 5 2026-05-25 2026-09-25 ok
reg-ltiidp.coloradotech.edu 12 2026-07-31 2026-10-02 nxdomain
int-ltiidp.coloradotech.edu 14 2026-07-15 2026-09-30 ok
smartcatalogiq.coloradotech.edu 3 2026-03-18 2026-08-18 ok
*.denver.coloradotech.edu 21 2026-04-12 2026-10-05 —
autodiscover.coloradotech.edu 2 2025-12-26 2026-01-25 ok
qr.coloradotech.edu 1 2026-09-11 2026-09-11 ok
*.cs.coloradotech.edu 21 2026-04-12 2026-10-05 —
class.coloradotech.edu 19 2026-05-13 2026-10-04 ok
smartcatalogiq-proxy.coloradotech.edu 2 2026-03-18 2026-08-18 ok

Programmatic access, with DNS A records: API GET /v1/hosts/coloradotech.edu (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/coloradotech.edu.