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.

20 hosts · 268 ms

HostCertsFirst seenLast seen
flexrule.com 1 2026-05-04 2026-05-04
*.flexrule.com 1 2026-05-04 2026-05-04
staging62.flexrule.com 5 2026-04-29 2026-08-27
www.staging62.flexrule.com 5 2026-04-29 2026-08-27
staging58.flexrule.com 5 2026-05-04 2026-09-01
www.staging58.flexrule.com 5 2026-05-04 2026-09-01
staging60.resource.flexrule.com 5 2026-05-09 2026-09-06
www.staging60.resource.flexrule.com 5 2026-05-09 2026-09-06
staging61.resource.flexrule.com 4 2026-06-06 2026-10-04
www.staging61.resource.flexrule.com 4 2026-06-06 2026-10-04
staging48.resource.flexrule.com 4 2026-04-12 2026-08-10
www.staging48.resource.flexrule.com 4 2026-04-12 2026-08-10
ci.flexrule.com 4 2026-05-03 2026-07-29
dmn.flexrule.com 6 2026-05-06 2026-09-03
www.dmn.flexrule.com 6 2026-05-06 2026-09-03
git.flexrule.com 4 2026-05-03 2026-07-29
test.flexrule.com 5 2026-04-27 2026-08-25
www.test.flexrule.com 5 2026-04-27 2026-08-25
staging50.academy.flexrule.com 5 2026-04-28 2026-08-26
www.staging50.academy.flexrule.com 5 2026-04-28 2026-08-26

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