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.

2 hosts · 243 ms

HostCertsFirst seenLast seen
data.mail.mktg.truist.com 4 2025-08-30 2026-09-01
cdn.mail.mktg.truist.com 1 2026-02-01 2026-02-01

Programmatic access: API GET /v1/hosts/mail.mktg.truist.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.mktg.truist.com.