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.

6 hosts · 246 ms

HostCertsFirst seenLast seen
feiinc.com 9 2025-10-14 2026-09-25
*.feiinc.com 1 2026-05-28 2026-05-28
estore.feiinc.com 2 2026-01-25 2026-06-22
webapp.feiinc.com 4 2025-10-06 2026-08-17
www.feiinc.com 8 2025-10-14 2026-10-05
survey.feiinc.com 4 2025-10-06 2026-08-17

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