What is KoSIT?

KoSIT publishes validation configurations (rule sets) that define exactly which checks an XRechnung invoice must pass. The validator engine processes an invoice XML against these rules and produces a structured report indicating pass/fail for each rule. Invoice Navigator integrates KoSIT natively: after our remediation engine fixes structural errors, the corrected invoice runs through KoSIT for independent verification. This ensures our fixes actually resolve the compliance issues — not just our own validation, but the same validation German authorities use.

Using KoSIT for revalidation means Invoice Navigator's compliance results match what the German government sees. When you submit an invoice that passed our KoSIT revalidation, you can be confident it will also pass on the receiving end. The Evidence Pack documents this KoSIT result, giving auditors verifiable proof of compliance.

You don't need to set up KoSIT yourself — Invoice Navigator handles it. When you validate an invoice through our API or Validator tool, KoSIT revalidation is included automatically. The result appears in your Evidence Pack.