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.

11 hosts · 314 ms

HostCertsFirst seenLast seenDNS
dtx.nl 5 2026-05-10 2026-09-03 ok
wgdim00.dtx.nl 2 2026-05-15 2026-05-15 ok
api.dtx.nl 1 2026-04-07 2026-04-07 ok
cspportal.dtx.nl 2 2026-02-23 2026-06-15 ok
classroom.dtx.nl 2 2026-02-18 2026-07-10 ok
cipp.dtx.nl 5 2026-02-22 2026-09-15 ok
order.dtx.nl 8 2026-05-01 2026-08-27 nxdomain
docs.dtx.nl 2 2026-02-24 2026-07-14 ok
freshrss.dtx.nl 2 2026-03-12 2026-06-26 ok
scientiae-dev.dtx.nl 2 2026-09-18 2026-09-18 ok
www.dtx.nl 5 2026-05-10 2026-09-03 ok

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