Find every subdomain
of a domain.

Every hostname under a domain that ever appeared in a public TLS certificate — with certificate counts, first/last seen and live DNS status.

2 hosts · 302 ms

HostCertsFirst seenLast seenDNS
devotedhealth.com 2 2025-06-15 2026-05-16 ok
www.devotedhealth.com 2 2025-06-15 2026-05-16 ok

Programmatic access, with DNS A records: API GET /v1/hosts/devotedhealth.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/devotedhealth.com.