PEPPOL Invoice Validation: How Belgian E-Invoices Are Validated Before Delivery
Not every file sent via PEPPOL is a valid invoice. The PEPPOL network applies multiple layers of validation before an invoice reaches the recipient — checking that the document is correctly structured, contains all required fields, and complies with Belgian and EU business rules. Here's how it works and what Eurobillr does to ensure your invoices always pass.
What Is PEPPOL Invoice Validation?
PEPPOL invoice validation is the automated process of checking that an electronic invoice meets all technical and business requirements before it is delivered to the recipient. Validation happens at the Access Point level (your PEPPOL service provider) before transmission. An invoice that fails validation is rejected and never reaches the recipient.
Layers of PEPPOL Validation
1. Schema Validation (XML Structure)
The invoice must be a valid XML document conforming to the PEPPOL BIS Billing 3.0 schema (based on UBL 2.1 or UN/CEFACT CII). This checks that all required XML elements are present, correctly named, and in the right order. A missing or misspelled XML tag fails schema validation immediately.
2. Business Rule Validation (Schematron)
Beyond structure, PEPPOL applies over 100 business rules defined in Schematron validation files. These check logical correctness:
- Invoice total must equal the sum of line item totals
- VAT amount must match the declared VAT rate applied to the taxable amount
- Mandatory fields (supplier name, address, VAT number, invoice date, payment terms) must be populated
- Currency codes must be valid ISO 4217 codes
- Date formats must conform to ISO 8601
3. Belgian-Specific Business Rules
Belgium applies additional national business rules on top of the core PEPPOL rules:
- Belgian VAT numbers must be in the correct format (BE + 10 digits)
- KBO/BCE number must be present and valid
- Applicable Belgian VAT rates must be used (21%, 12%, 6%, 0%)
- The supplier must be registered on the PEPPOL network (verified via SMP lookup)
4. Recipient Lookup (SMP/SML)
Before transmission, the Access Point looks up whether the recipient's PEPPOL ID is registered and capable of receiving the specific document type. If the recipient is not registered or has not enabled receiving invoices, the transmission is rejected with a clear error.
What Happens When Validation Fails?
If an invoice fails validation at any layer, it is rejected before delivery. The sender receives an error notification with details of what failed. The invoice never reaches the recipient — there is no risk of delivering an invalid invoice.
Common rejection reasons:
- Invalid or unregistered recipient PEPPOL ID
- Missing mandatory field (e.g. client VAT number for B2B invoices)
- VAT calculation mismatch (line total × VAT rate ≠ declared VAT amount)
- Invalid VAT number format
How Eurobillr Handles Validation
Eurobillr validates your invoice before it is submitted to the PEPPOL network:
- Real-time field validation — required fields are checked as you fill in the invoice form
- VAT number verification — Belgian and EU VAT numbers are validated against KBO and VIES databases
- Recipient PEPPOL ID check — Eurobillr verifies the recipient is registered before you send
- Mathematical consistency check — line totals, VAT amounts, and invoice total are verified for consistency
If anything is wrong, Eurobillr shows you exactly what needs to be fixed before the invoice leaves your account — not after rejection by the network.