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.

6 hosts · 238 ms

HostCertsFirst seenLast seen
korsec.co.kr 6 2025-09-23 2026-10-14
*.korsec.co.kr 3 2026-02-20 2026-07-29
reissuetest1.korsec.co.kr 3 2026-08-31 2026-09-07
alpha2newroot.korsec.co.kr 2 2026-06-12 2026-07-29
alphanewroot.korsec.co.kr 2 2026-06-11 2026-07-29
www.korsec.co.kr 4 2025-09-23 2026-10-14

Programmatic access: API GET /v1/hosts/korsec.co.kr (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/korsec.co.kr.