Find every subdomain
of a domain.

Every hostname under a domain that ever appeared in a public TLS certificate — with certificate counts and first/last seen dates.

9 hosts · 206 ms

HostCertsFirst seenLast seen
northmill.fi 2 2026-03-30 2026-08-30
customs-reporting.northmill.fi 1 2026-04-17 2026-04-17
klick.northmill.fi 11 2026-06-02 2026-10-01
n.northmill.fi 5 2026-05-07 2026-09-04
mta-sts.info.northmill.fi 1 2025-11-17 2025-11-17
mta-sts.northmill.fi 1 2026-02-09 2026-02-09
mta-sts.news.northmill.fi 1 2025-11-18 2025-11-18
customs-reporting-dev.northmill.fi 1 2026-05-07 2026-05-07
www.northmill.fi 2 2026-03-30 2026-08-30

Programmatic access: API GET /v1/hosts/northmill.fi (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/northmill.fi.