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.

5 hosts · 248 ms

HostCertsFirst seenLast seen
britannicaeducation.com 27 2026-04-23 2026-10-05
*.britannicaeducation.com 11 2026-04-23 2026-10-05
email.britannicaeducation.com 6 2026-05-01 2026-08-27
pages.britannicaeducation.com 8 2026-05-01 2026-08-27
www.britannicaeducation.com 12 2026-04-25 2026-08-21

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