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.

6 hosts · 266 ms

HostCertsFirst seenLast seenDNS
isi-app.de 10 2026-04-22 2026-09-29 ok
*.isi-app.de 7 2026-04-22 2026-08-18 —
diga.isi-app.de 4 2026-07-29 2026-09-30 ok
www.diga.isi-app.de 2 2026-07-29 2026-07-29 nxdomain
dev.isi-app.de 4 2026-04-18 2026-08-26 ok
www.isi-app.de 3 2026-07-27 2026-09-27 ok

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