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 · 220 ms

HostCertsFirst seenLast seenDNS
guardiosecurity.com 6 2026-05-08 2026-09-03 ok
*.guardiosecurity.com 6 2026-05-08 2026-09-03 —
links.guardiosecurity.com 3 2026-04-28 2026-08-16 ok

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