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 · 207 ms

HostCertsFirst seenLast seenDNS
data.email.verizon.com 4 2025-09-09 2026-09-11 ok
unsubscribe.email.verizon.com 2 2025-12-24 2025-12-24 ok
cdn.email.verizon.com 2 2025-07-06 2026-06-06 ok

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