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.

3 hosts · 250 ms

HostCertsFirst seenLast seenDNS
penguinrandomhouse.co.nz 2 2025-10-03 2025-12-28 ok
autodiscover.penguinrandomhouse.co.nz 2 2025-09-22 2026-09-18 ok
www.penguinrandomhouse.co.nz 3 2025-10-03 2026-06-11 ok

Programmatic access, with DNS A records: API GET /v1/hosts/penguinrandomhouse.co.nz (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/penguinrandomhouse.co.nz.