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 · 308 ms

HostCertsFirst seenLast seenDNS
ksk-weilburg.de 2 2026-04-20 2026-10-06 ok
psd2-xs2a.ksk-weilburg.de 3 2025-09-02 2026-08-14 nxdomain
module.ksk-weilburg.de 2 2026-04-20 2026-10-06 ok
mail.ksk-weilburg.de 5 2026-05-05 2026-09-02 ok
www.ksk-weilburg.de 2 2026-04-20 2026-10-06 ok

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