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 · 251 ms

HostCertsFirst seenLast seenDNS
spk-hef.de 2 2026-04-20 2026-10-06 ok
psd2-xs2a.spk-hef.de 2 2025-08-05 2026-06-23 nxdomain
module.spk-hef.de 2 2026-04-20 2026-10-06 ok
mailing.spk-hef.de 5 2026-04-23 2026-08-20 ok
www.spk-hef.de 2 2026-04-20 2026-10-06 ok

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