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.

5 hosts · 295 ms

HostCertsFirst seenLast seenDNS
sierraexpedite.com 7 2026-04-15 2026-09-17 ok
*.sierraexpedite.com 6 2026-04-15 2026-09-17 —
stage.sierraexpedite.com 2 2026-09-18 2026-09-18 ok
tms.sierraexpedite.com 1 2026-09-15 2026-09-15 ok
www.sierraexpedite.com 1 2026-09-14 2026-09-14 ok

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