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.

2 hosts · 195 ms

HostCertsFirst seenLast seen
saginawcountymi.gov 18 2025-08-19 2026-09-10
*.saginawcountymi.gov 18 2025-08-19 2026-09-10

Programmatic access: API GET /v1/hosts/saginawcountymi.gov (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/saginawcountymi.gov.