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.

4 hosts · 288 ms

HostCertsFirst seenLast seenDNS
kroff.com 7 2026-04-30 2026-09-11 ok
executivedashboard.kroff.com 3 2026-06-25 2026-08-25 ok
mailtrackio.kroff.com 1 2026-08-13 2026-08-13 ok
www.kroff.com 8 2026-04-29 2026-09-11 ok

Programmatic access, with DNS A records: API GET /v1/hosts/kroff.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/kroff.com.