PEPPOL and Mercurius Platform in Belgium

Starting January 2026, Belgium will mandate e-invoicing for all VAT-liable B2B transactions, aligning with EU standards for a digitized and transparent invoicing ecosystem. Businesses must adapt to two key components: the Mercurius Platform, which processes and routes e-invoices, and the PEPPOL framework, which provides the technical standards and protocols for seamless data exchange.

This article explores the roles of these components in Belgium’s e-invoicing mandate, their functionalities, and how businesses can adapt.

What is E-Invoicing?

E-invoicing, or electronic invoicing, is the process of issuing, transmitting, and receiving invoices in a structured, digital format that supports automated processing. Unlike paper invoices or unstructured PDFs, e-invoices adhere to a standardized format that ensures compatibility across different systems and jurisdictions.

In the European Union, including Belgium, the EN16931 standard governs e-invoicing. This standard ensures that all necessary invoice details are captured in a structured way, making the invoice machine-readable and compatible with the recipient’s system.

Belgium’s E-Invoicing Mandate: Two Core Components

Belgium’s e-invoicing ecosystem consists of two critical components:

The Mercurius Platform: Processing Hub

The Mercurius Platform is Belgium’s centralized portal for e-invoice processing. Acting as a “mailroom,” it routes electronic invoices between senders (businesses) and recipients (public authorities or other businesses).

Key Functions of the Mercurius Platform:

• Invoice Submission and Routing: Ensures e-invoices are correctly transmitted to the intended recipients.
• Interoperability Support: Aligns with the PEPPOL framework, ensuring invoices meet EU standards.
• Manual Invoice Submission: Allows businesses without automated systems to submit invoices manually.
• Track and Trace: Provides real-time updates on invoice status for both senders and recipients.
• Document Conversion: Converts machine-readable invoices (XML) to human-readable formats (PDF), ensuring inclusivity for smaller entities.

The PEPPOL Framework: Standards and Network

PEPPOL, or Pan-European Public Procurement On-Line, is the framework that underpins the technical and operational standards for e-invoicing in Belgium. It serves as the backbone of the e-invoicing system, ensuring seamless and secure data exchange.

Key Functions of the PEPPOL Framework:

• Standardized Data Format: Defines the structure of e-invoices using the EN16931 standard to ensure compatibility across the EU.
• Interoperable Network: Connects senders and recipients through certified Access Points, enabling seamless data exchange between different software systems.
• Compliance Protocols: Sets rules for authenticity, data integrity, and legal validity to ensure secure transactions.
• Global Reach: Extends beyond Europe to countries like Singapore, Australia, and New Zealand, enabling cross-border invoicing.

Role of the Mercurius Platform in Belgium’s E-Invoicing

The Mercurius Platform is critical to Belgium’s e-invoicing strategy, particularly for public procurement (B2G transactions). By 2026, it will also handle B2B transactions, ensuring compliance with the e-invoicing mandate.

How Mercurius Works

1. Invoice Submission: Businesses generate structured e-invoices and submit them via the Mercurius portal or through integrated Peppol-compliant software.
2. Routing: Mercurius routes the invoice to the correct recipient (public authority or business).
3. Acknowledgment and Processing: Recipients acknowledge receipt, process the invoice, and return response documents (e.g., approvals or rejections) through the platform.
4. Archive and Reporting: Invoices are archived for compliance purposes, with status tracking and reporting features available for both senders and recipients.

Benefits of the Mercurius Platform

• Centralized Management: Simplifies invoicing for businesses by providing a single point of interaction with public authorities.
• Flexibility: Supports both automated and manual submissions, making it accessible for businesses of all sizes.
• Transparency: Real-time tracking enhances visibility and reduces processing delays.

Role of PEPPOL in Belgium’s E-Invoicing

PEPPOL plays a critical role in Belgium’s e-invoicing ecosystem by providing a unified framework for secure and efficient data exchange, eliminating the inefficiencies of fragmented systems and incompatible formats. Managed by Belgium's Federal Public Service Policy and Support (BOSA) as the official Peppol authority, it ensures compliance with EU standards. Additionally, a national recipient register enables businesses to easily identify and connect with Peppol-compliant entities, facilitating seamless invoicing processes.

How PEPPOL Supports E-Invoicing

• Standardized Invoice Format: Ensures invoices comply with the EN16931 standard for compatibility and automation across systems.
• Certified Access Points: Connect businesses to the PEPPOL network through service providers for secure invoice exchange.
• Interoperable Network: Enables seamless invoicing between participants across the network, domestically and internationally.
• Data Security and Compliance: Guarantees encrypted, secure data transmission and adherence to EU regulations for authenticity and integrity.
• Integration with Belgium’s Mercurius Platform: Facilitates smooth communication between businesses and public authorities within Belgium’s e-invoicing ecosystem.

Benefits of PEPPOL in Belgium

• Simplifies Compliance: PEPPOL ensures all invoices adhere to European standards, such as EN16931, reducing the likelihood of errors or rejections. This simplifies regulatory compliance for businesses and public authorities.
• Enhances Efficiency: By automating data exchange and enabling secure transmission, PEPPOL eliminates manual processes, reduces processing time, and minimizes human errors in the invoicing workflow.
• Supports Scalability: PEPPOL is designed to cater to businesses of all sizes, from small enterprises to large multinational corporations. It supports both domestic and international transactions, making it adaptable as businesses grow.
• Fosters Connectivity: With a single connection to a certified Access Point, businesses can exchange invoices with all participants in the PEPPOL network, creating a vast and interoperable ecosystem of trading partners.
• Enables Seamless Cross-Border Transactions: PEPPOL facilitates international trade by providing a standardized invoicing format compatible across borders. Businesses in Belgium can exchange e-invoices with trading partners in any country within the PEPPOL network, ensuring compliance with cross-border regulations and fostering global business opportunities.

How to Get Started with PEPPOL and Mercurius in Belgium?

1. Assess Your Current System: Determine whether your invoicing software is Peppol-compliant and supports integration with the Mercurius platform.
2. Register for PEPPOL: Work with a certified Access Point provider to obtain a unique Peppol ID.
3. Integrate with Mercurius: Connect your business system to the Mercurius platform or use its manual submission features.
4. Validate Compliance: Test e-invoices against EN16931 standards to ensure they meet regulatory requirements.
5. Train Staff: Educate employees on using Peppol and Mercurius to streamline invoicing workflows.

Conclusion

Belgium’s transition to mandatory e-invoicing by 2026 marks a significant step toward digitizing financial processes, ensuring compliance, and improving efficiency. The Mercurius platform and PEPPOL framework form the foundation of this ecosystem, providing the infrastructure and standards necessary for seamless invoicing.

For businesses in Belgium, preparing for this transition is essential. By leveraging PEPPOL and the Mercurius platform, enterprises can not only ensure compliance but also unlock the benefits of cost savings, faster processing, and enhanced operational transparency.