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.

4 hosts · 209 ms

HostCertsFirst seenLast seen
cloud.e.simonandschuster.com 1 2026-01-06 2026-01-06
image.e.simonandschuster.com 3 2026-03-16 2026-08-03
click.e.simonandschuster.com 1 2026-01-11 2026-01-11
view.e.simonandschuster.com 1 2026-01-06 2026-01-06

Programmatic access: API GET /v1/hosts/e.simonandschuster.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/e.simonandschuster.com.