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.

7 hosts · 196 ms

HostCertsFirst seenLast seen
aclj.org 1 2025-12-18 2025-12-18
*.aclj.org 1 2025-12-18 2025-12-18
give.aclj.org 6 2026-06-04 2026-10-04
image.email.aclj.org 4 2025-07-12 2026-08-31
click.email.aclj.org 1 2025-11-04 2025-11-04
view.email.aclj.org 1 2025-11-05 2025-11-05
t.aclj.org 9 2026-04-15 2026-09-16

Programmatic access: API GET /v1/hosts/aclj.org (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/aclj.org.