Structured E-Invoicing in Belgium: Requirements, Formats & Compliance

From January 1, 2026, Belgium requires all business-to-business (B2B) invoices to be sent as structured electronic invoices. Under the Belgium e-invoicing mandate, Belgian companies must issue, receive, and store invoices in a machine-readable format, no more paper or PDF invoices for domestic B2B sales.

The backbone of Belgium’s system is the Peppol framework and the use of the EN 16931 standard. A structured e-invoice in Belgium is a machine-readable UBL XML invoice, compliant with EN 16931 and Peppol BIS 3.0 standards, used for B2B transactions.

What is E-Invoicing?

E-invoicing is the creation, exchange, and storage of invoices in a digital format that software can read automatically. Unlike PDFs or paper invoices which are just images or text electronic invoices use standardized data formats. This allows accounting systems to process invoices instantly, with no manual entry.

A structured e-invoice is an invoice issued in a specific, standardized, machine-readable format. In Belgium, this means using UBL XML files built to the European EN 16931 standard, delivered through the Peppol network. Each data point such as buyer, seller, VAT number, amounts, and dates has its own field in the XML structure, making it easy for accounting software to extract and process the data automatically.

• Not a PDF or image: Structured e-invoices are not human-readable documents like PDFs. Instead, they’re data files designed for systems, not people.
• Automated processing: The format enables direct system-to-system exchange, speeding up invoice approval and reducing errors.
• Legally required: From 2026, only structured e-invoices will be accepted for B2B transactions between VAT-registered entities in Belgium.
• Compliance standard: Structured e-invoices in Belgium must follow the Peppol BIS 3.0 specification and comply with EN 16931, the EU’s common e-invoice data model.

Key Requirements in Belgium for Structured E-Invoicing

Belgium’s 2026 e-invoicing law sets strict technical, legal, and operational rules for every VAT registered business. Here are some of them

1. Structured Format Mandatory: All domestic B2B invoices must be issued as structured electronic invoices—specifically, Peppol BIS 3.0 UBL XML files. 

2. Use of the Peppol Network: Peppol network connects companies and their service providers (Access Points).

3. Ability to Receive E-Invoices: Every VAT-registered business must also be able to receive structured e-invoices through their Access Point. 

4. Complete Content and Data: Invoices must include all mandatory VAT information:

• Supplier and buyer legal details and VAT numbers
• Invoice number and date
• Item descriptions, quantities, prices
• Taxable amounts, VAT rates, and totals
• Payment terms and instructions

5. Timeliness and Real-Time Potential: E-invoices must be issued promptly, following VAT law (after supply). 

6. Archiving and Integrity: Businesses must keep structured e-invoices in their original format for at least 7 years. 

7. Correction and Credit Notes: If corrections are needed, credit notes or corrections must also be sent as structured e-invoices through Peppol.

Accepted Formats and Standards for Structured E-Invoice in Belgium

Belgium’s e-invoicing law requires invoices to be in a structured, machine-readable format for full automation and compliance. Here are the  accepted formats

• Main standard: Peppol BIS Billing 3.0 UBL XML (EN 16931 compliant)
• Alternative (by mutual agreement only): Other EN 16931-compliant formats (such as EDIFACT INVOIC or Factur-X/ZUGFeRD hybrid XML+PDF), if both parties accept and all legal data is present.

Steps to Generate a Structured E-Invoice

Here is how Belgian businesses can generate structured E-Invoice

1. ERP Integration with Peppol Access Point
   Connect your ERP or accounting software with a certified Peppol Access Point (AP). Many leading ERPs have built-in Peppol integration modules or connectors.
2. Invoice Data Preparation
   Enter all required invoice details in your ERP. The system will use these data fields to build the structured e-invoice (UBL XML) as per EN 16931.
3. Data Validation and Enrichment
   Before sending, the AP validates the invoice for format errors, missing fields, and compliance with Belgian rules. Some APs offer data enrichment, automatically correcting common issues.
4. Formatting and Transmission
   The validated e-invoice is formatted to the Peppol BIS 3.0 UBL XML specification. The AP transmits the invoice securely over the Peppol network to the recipient’s AP, using their Peppol ID (typically based on VAT number).
5. Acknowledgment and Receipt
   The recipient’s AP delivers the invoice to their system. Status updates and delivery confirmations are provided, allowing both sender and receiver to track the invoice end-to-end.
6. Archiving
   Store the structured e-invoice XML in your digital archive, with access controls and backup. Ensure you can reproduce and display it for audits or legal purposes.

Why Choose ClearTax for Compliant E-Invoice Generation?

ClearTax offers a proven, certified Peppol Access Point solution, fully compliant with Belgian and EU regulations.

• Peppol Ready: ClearTax is an officially certified Peppol Access Point, guaranteeing seamless, secure invoice exchange.
• EN 16931 & Peppol BIS 3.0 Compliance: All e-invoices generated meet mandatory Belgian standards, with built-in data validation.
• ERP Integration: ClearTax supports integration with leading ERP and accounting systems, automating invoice creation and transmission.
• Simple Setup: Quick onboarding, user-friendly dashboards, and expert support for transition and training.
• Future-Proof: Ready for Belgium’s 2026 e-invoicing mandate, 2028 e-reporting, and evolving EU compliance requirements.
• Reliability: High uptime, robust data security, and support for managing exceptions or contingencies.

Conclusion

Every VAT-registered business in Belgium must issue, receive, and archive invoices as machine-readable data files starting 2026. Only EN 16931-compliant formats are accepted; PDFs and scanned images are no longer valid for B2B. The goal is to standardize and automate invoicing, ensuring faster, more accurate processing and compliance with EU standards.

The backbone of compliance in Belgium is the use of Peppol BIS 3.0 UBL XML files, fully aligned with the EN 16931 standard and transmitted over the Peppol network. Businesses need to upgrade their ERP systems, validate invoice content, and ensure they can both send and receive structured e-invoices through certified Access Points. ClearTax offers a certified, Peppol-ready platforms that simplify integration, validation, and secure e-invoice exchange.