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 · 250 ms

HostCertsFirst seenLast seenDNS
fideon.nl 10 2026-05-19 2026-08-18 ok
*.fideon.nl 7 2026-05-19 2026-08-18 —
imtiweb01.fideon.nl 5 2026-05-30 2026-09-27 ok
merkbewaking.fideon.nl 1 2026-07-03 2026-07-03 ok
www.fideon.nl 3 2026-05-29 2026-08-10 ok

Programmatic access, with DNS A records: API GET /v1/hosts/fideon.nl (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/fideon.nl.