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.

3 hosts · 288 ms

HostCertsFirst seenLast seenDNS
helgeheupel.com 1 2026-06-29 2026-06-29 nodata
mta-sts.helgeheupel.com 3 2026-06-29 2026-08-28 ok
www.helgeheupel.com 3 2026-06-29 2026-09-16 nodata

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