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.

3 hosts · 182 ms

Download CSV
HostCertsFirst seenLast seen
m1.update.helsana.ch 1 2025-12-08 2025-12-08
res1.update.helsana.ch 1 2025-12-07 2025-12-07
t1.update.helsana.ch 1 2025-12-08 2025-12-08

Programmatic access: API GET /v1/hosts/update.helsana.ch (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/update.helsana.ch.