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 · 288 ms

HostCertsFirst seenLast seen
studeersnel.nl 25 2025-07-07 2026-09-19
*.studeersnel.nl 25 2025-07-07 2026-09-19
infographic.studeersnel.nl 3 2026-06-13 2026-08-16
stuudle.studeersnel.nl 5 2026-04-22 2026-08-22
*.staging.studeersnel.nl 5 2025-10-16 2026-09-16
mainframe.staging.studeersnel.nl 5 2026-05-11 2026-09-10
blog.studeersnel.nl 6 2026-05-22 2026-09-17
lesson-plans.studeersnel.nl 5 2026-05-03 2026-09-02

Programmatic access: API GET /v1/hosts/studeersnel.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/studeersnel.nl.