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 · 288 ms

HostCertsFirst seenLast seen
b365.com 6 2026-05-25 2026-09-20
*.b365.com 6 2026-05-25 2026-09-20
m.b365.com 5 2026-05-07 2026-09-04
clicks.b365.com 2 2025-07-21 2026-08-03

Programmatic access: API GET /v1/hosts/b365.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/b365.com.