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.

5 hosts · 229 ms

HostCertsFirst seenLast seenDNS
cloud.email.hsn.com 1 2026-05-11 2026-05-11 ok
image.email.hsn.com 3 2025-06-28 2026-07-16 ok
click.email.hsn.com 1 2026-02-19 2026-02-19 ok
pages.email.hsn.com 2 2026-03-02 2026-08-04 ok
view.email.hsn.com 2 2026-03-02 2026-08-04 ok

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