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 · 246 ms

HostCertsFirst seenLast seenDNS
cloud.email.cpisecurity.com 2 2025-06-21 2026-06-08 ok
image.email.cpisecurity.com 4 2026-03-13 2026-09-08 ok
click.email.cpisecurity.com 2 2025-06-18 2026-06-08 ok
view.email.cpisecurity.com 2 2025-06-18 2026-06-05 ok

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