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.

3 hosts · 203 ms

HostCertsFirst seenLast seen
newsletterit.esprinet.com 2 2025-06-30 2026-06-29
web.newsletterit.esprinet.com 2 2025-09-15 2026-09-14
www.newsletterit.esprinet.com 2 2025-06-30 2026-06-29

Programmatic access: API GET /v1/hosts/newsletterit.esprinet.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/newsletterit.esprinet.com.