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.

1 host · 246 ms

HostCertsFirst seenLast seen
*.duke-energyalert.com 1 2026-02-12 2026-02-12

Programmatic access: API GET /v1/hosts/duke-energyalert.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/duke-energyalert.com.