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.

3 hosts · 259 ms

HostCertsFirst seenLast seen
kolodev.com 2 2025-08-09 2026-06-20
mta-sts.kolodev.com 1 2026-05-14 2026-05-14
www.kolodev.com 2 2025-08-09 2026-06-20

Programmatic access: API GET /v1/hosts/kolodev.com (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/kolodev.com.