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 · 311 ms

HostCertsFirst seenLast seenDNS
roberthalf.de 1 2025-12-16 2025-12-16 ok
*.roberthalf.de 1 2025-12-16 2025-12-16 —
www.m.roberthalf.de 1 2025-12-16 2025-12-16 ok
tags.roberthalf.de 2 2025-07-02 2026-06-02 ok
collect.roberthalf.de 2 2025-07-02 2026-06-02 ok

Programmatic access, with DNS A records: API GET /v1/hosts/roberthalf.de (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/roberthalf.de.