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.

7 hosts · 315 ms

HostCertsFirst seenLast seenDNS
topdoek.nl 5 2026-04-28 2026-09-28 ok
e.topdoek.nl 5 2026-05-23 2026-09-19 ok
staging.topdoek.nl 4 2026-05-20 2026-09-29 nxdomain
metrics.topdoek.nl 5 2026-04-20 2026-10-01 ok
test.topdoek.nl 3 2026-09-08 2026-10-02 ok
sst.topdoek.nl 11 2026-05-05 2026-09-29 ok
www.topdoek.nl 5 2026-04-28 2026-09-28 ok

Programmatic access, with DNS A records: API GET /v1/hosts/topdoek.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/topdoek.nl.