Guide · Updated May 2026
Markdown exportAuthoritative E-Invoice Validation Guide
Resolve authoritative validation warnings, manage connection timeouts, interpret KoSIT validator reports, and ensure EN16931 compliance.
Understanding authoritative validation
While local validators verify basic structure, official e-invoice compliance requires passing authoritative validation. This involves executing official Schematron rules from the KoSIT validator for German standards, or Peppol BIS Billing 3.0 specifications.
Passing this step provides legal proof that the generated UBL or CII XML complies with European standards.
Handling temporary outages
Use these points as the practical checks for this section.
- KoSIT or Peppol web service starting or down for maintenance.
- Network latency causing connection timeouts between the gateway and official servers.
- High-traffic periods resulting in temporary 504 Gateway Timeout responses.
Developer resilience policy
If the authoritative validator service is unreachable, Invoice Converter returns a VALIDATION_SERVICE_UNAVAILABLE error.
In production environments, you should catch this state and place the invoice in a retry queue. Never skip validation for public sector buyers (like those requiring a Leitweg-ID) as they will reject non-validated invoices.
Troubleshooting validation errors
Use these points as the practical checks for this section.
- Check that the BuyerReference or Leitweg-ID matches the official registry format.
- Verify that currency codes conform to standard ISO 4217.
- Ensure that tax subtotals exactly match the sum of line item tax values.
- Review the returned XML report in the response payload for exact Schematron rule IDs like BR-DE-15.