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 · 284 ms

HostCertsFirst seenLast seenDNS
sparkasse-siegen.de 4 2026-04-16 2026-10-02 ok
psd2-xs2a.sparkasse-siegen.de 2 2025-07-10 2026-06-02 nxdomain
module.sparkasse-siegen.de 4 2026-04-16 2026-10-02 ok
mailing.sparkasse-siegen.de 5 2026-05-06 2026-09-02 ok
www.sparkasse-siegen.de 4 2026-04-16 2026-10-02 ok

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