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 · 267 ms

HostCertsFirst seenLast seenDNS
cloud.mail.creativeplanning.com 1 2026-02-22 2026-02-22 ok
image.mail.creativeplanning.com 5 2026-01-29 2026-09-23 ok
click.mail.creativeplanning.com 2 2026-02-22 2026-02-22 ok
view.mail.creativeplanning.com 1 2026-02-22 2026-02-22 ok

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