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 · 285 ms

HostCertsFirst seenLast seenDNS
achmea.com 3 2025-08-14 2026-08-24 ok
event.achmea.com 1 2026-01-14 2026-01-14 ok
*.event.achmea.com 1 2026-01-14 2026-01-14 —
f.event.achmea.com 6 2026-05-02 2026-10-01 ok
www.achmea.com 3 2025-08-14 2026-08-24 ok

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