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.

5 hosts · 303 ms

HostCertsFirst seenLast seenDNS
ksk-diepholz.de 2 2025-12-22 2026-09-01 ok
psd2-xs2a.ksk-diepholz.de 3 2025-09-02 2026-08-14 nxdomain
module.ksk-diepholz.de 2 2026-01-12 2026-09-01 ok
mailing.ksk-diepholz.de 5 2026-05-08 2026-09-05 ok
www.ksk-diepholz.de 2 2026-01-12 2026-09-01 ok

Programmatic access, with DNS A records: API GET /v1/hosts/ksk-diepholz.de (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/ksk-diepholz.de.