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.

9 hosts · 382 ms

HostCertsFirst seenLast seen
ca.emails.synchrony.com 1 2026-01-28 2026-01-28
e.emails.synchrony.com 1 2026-01-28 2026-01-28
ca-clf.emails.synchrony.com 1 2026-01-28 2026-01-28
ca-ha-clf.emails.synchrony.com 1 2026-01-28 2026-01-28
ca-csf.emails.synchrony.com 1 2026-01-28 2026-01-28
ca-ha-csf.emails.synchrony.com 1 2026-01-28 2026-01-28
preferences.emails.synchrony.com 16 2026-05-14 2026-09-09
images.emails.synchrony.com 1 2026-01-28 2026-01-28
view.emails.synchrony.com 1 2026-01-28 2026-01-28

Programmatic access: API GET /v1/hosts/emails.synchrony.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/emails.synchrony.com.