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 · 329 ms

HostCertsFirst seenLast seenDNS
strayeruniversity.edu 17 2026-05-22 2026-09-23 ok
*.strayeruniversity.edu 17 2026-05-22 2026-09-23 —
learning.strayeruniversity.edu 3 2026-06-11 2026-08-20 ok
app.learning.strayeruniversity.edu 3 2026-06-11 2026-08-20 ok
images.learning.strayeruniversity.edu 6 2026-06-11 2026-08-20 ok

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