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.

9 hosts · 266 ms

HostCertsFirst seenLast seenDNS
somi.nl 6 2025-10-27 2026-09-03 ok
*.somi.nl 1 2025-10-27 2025-10-27 —
stage.somi.nl 5 2026-05-06 2026-09-03 ok
investeren.somi.nl 4 2026-06-15 2026-09-15 ok
app.somi.nl 2 2026-08-31 2026-10-05 ok
datarequests.somi.nl 5 2026-05-23 2026-09-19 ok
at.somi.nl 5 2026-05-24 2026-09-21 ok
support.somi.nl 2 2026-05-06 2026-05-06 ok
www.somi.nl 5 2026-05-06 2026-09-03 ok

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