Find every subdomain
of a domain.

Every hostname under a domain that ever appeared in a public TLS certificate — with certificate counts and first/last seen dates.

8 hosts · 246 ms

HostCertsFirst seenLast seen
dua.com 13 2026-06-04 2026-09-30
*.dua.com 8 2026-06-04 2026-09-30
trail.dua.com 5 2026-06-09 2026-10-07
open.dua.com 16 2026-05-04 2026-08-30
fp.dua.com 1 2026-02-01 2026-02-01
help.dua.com 4 2026-06-12 2026-10-10
app.dua.com 2 2026-03-18 2026-08-18
www.dua.com 5 2026-06-13 2026-08-21

Programmatic access: API GET /v1/hosts/dua.com (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/dua.com.