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.

2 hosts · 156 ms

HostCertsFirst seenLast seen
data.emailservice.vattenfall.nl 2 2025-11-20 2025-11-20
cdn.emailservice.vattenfall.nl 2 2025-09-17 2026-08-18

Programmatic access: API GET /v1/hosts/emailservice.vattenfall.nl (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/emailservice.vattenfall.nl.