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.

7 hosts · 259 ms

HostCertsFirst seenLast seenDNS
ospa.de 2 2025-12-22 2026-08-26 ok
psd2-xs2a.ospa.de 2 2025-08-07 2026-06-25 nxdomain
module.ospa.de 2 2026-01-09 2026-08-26 ok
mailing.ospa.de 5 2026-04-27 2026-08-26 ok
mta-sts.mailing.ospa.de 3 2026-06-12 2026-09-03 ok
mta-sts.ospa.de 3 2026-06-12 2026-09-03 ok
www.ospa.de 2 2026-01-09 2026-08-26 ok

Programmatic access, with DNS A records: API GET /v1/hosts/ospa.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/ospa.de.