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.

3 hosts · 237 ms

HostCertsFirst seenLast seen
ad-flex.com 4 2026-04-20 2026-10-11
old.ad-flex.com 4 2026-04-20 2026-10-11
www.ad-flex.com 2 2025-06-26 2026-07-25

Programmatic access: API GET /v1/hosts/ad-flex.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/ad-flex.com.