Understanding eInvoicing with the Peppol Network

Electronic invoicing has become an increasingly popular and efficient way for businesses to manage their financial transactions. One of the leading standards in this domain is the Peppol network, which enables seamless exchange of electronic invoices and other business documents.
In this article, I’m going to introduce you to Peppol and how it works.

The Peppol Architecture

Peppol, short for “Pan-European Public Procurement On-Line”, is a set of technical specifications and governance rules that facilitate the exchange of electronic documents between organizations.

The Peppol architecture operates on a 4-Corner Model, involving a Sender (Supplier), a Receiver (Customer), and two Access Points (AP).
In this model, the Sender sends electronic invoices to their designated AP, which then routes the invoice to the Receiver’s AP for delivery.
This streamlined approach ensures secure and efficient transmission of electronic documents within the Peppol network, facilitating seamless communication between trading partners.

The 4-Corner Model is the backbone of the Peppol network.

So the invoice processing looks like:

• The Sender (Supplier) send the electronic invoice to their Access Point (AP)
• The Sender’s AP looks up the Receiver’s (Customer’s) information in the SML and SMP to determine the correct delivery route
• The Sender’s AP then transmits the electronic invoice to the Receiver’s AP.
• The Receiver’s AP delivers the electronic invoice to the Receiver (Customer).

What are SMP and SML?

The SMP (Service Metadata Publisher) and SML (Service Metadata Locator) work together in the Peppol network to facilitate the exchange of electronic documents. The SMP acts as a decentralized registry storing technical metadata about network participants, such as their capabilities and location. On the other hand, the SML serves as the central component that organizes routing within the network by maintaining information about all Peppol participants and the list of SMPs.

When an Access Point needs to connect with a specific SMP to discover the addressing details of a trading partner, it interacts with the SML to determine the appropriate SMP. This collaboration ensures that electronic documents are efficiently routed and delivered within the Peppol network, enhancing interoperability and secure communication between trading partners.

Peppol BIS V3 and UBL

In the realm of electronic document exchange, standardized formats play a pivotal role in ensuring seamless interoperability and efficient communication.

Within the Peppol network, the adoption of XML-based formats like Universal Business Language (UBL) and Peppol Business Interoperability Specifications (BIS) V3 is paramount. These formats, UBL and BIS V3, serve as the backbone for structuring and transmitting essential business documents, such as invoices, across the Peppol ecosystem.

UBL

UBL 2.1 serves as the foundation for structured electronic business documents. Developed by the Organization for the Advancement of Structured Information Standards (OASIS), UBL provides a common language for expressing business information in XML format. It defines a set of standard XML schemas for various business documents such as invoices, purchase orders, and shipping notices. UBL’s modular design facilitates interoperability and simplifies integration across different systems and industries.

Peppol BIS V3

Building upon UBL, the Peppol network incorporates specific guidelines and extensions tailored to electronic invoicing and procurement.
Peppol BIS Version 3 outlines the rules and syntax for exchanging business documents within the Peppol infrastructure. It ensures compatibility and uniformity among participants, enabling seamless communication and transaction processing across borders and industries.

The Peppol BIS V3 format adheres to the European standard EN 16931, which defines the core semantic model for electronic invoices. By adhering to the EN 16931 standard, the Peppol BIS V3 specifications ensure that electronic invoices exchanged within the Peppol network meet the essential requirements for content and structure.

Document Validation

The below diagram shows a simplified view of the validation steps of a document.

Step 1 : XML Validation - Syntax

The first step in validating a Peppol BIS V3 XML document involves checking its syntax to ensure it conforms to the XML standards.
This process verifies that the document structure and elements follow the rules and guidelines set for XML documents.

Step 2: UBL Format Compliance (Schema Validation)

Next, the document undergoes validation to ensure compliance with the Universal Business Language (UBL) format.
This validation confirms that the document adheres to the specific schema defined for UBL documents, including the correct structure, data types, and elements required for interoperability.

Step 3: CEN TC434 Rules

The CEN TC434 Rules refer to the guidelines and specifications established by the European Committee for Standardization (CEN) Technical Committee 434. These rules define the standard EN 16931, which serves as the semantic model for electronic invoicing. Compliance with CEN TC434 Rules ensures alignment with European invoicing standards.

Step 4: CIUS General Rules

The Core Invoice Usage Specification (CIUS) rules are additional guidelines developed by OpenPEPPOL to complement the EN 16931 standard within the PEPPOL network. These rules provide further specifications and restrictions for electronic invoicing, ensuring consistency and interoperability among participants.

Step 5: CIUS Country Rules

CIUS Country Rules are specific regulations and requirements tailored to individual countries within the PEPPOL network.
These rules address country-specific invoicing practices, legal requirements, and data formats, ensuring that electronic invoices meet the unique standards of each country for seamless cross-border transactions.

To summarize

By following these validation steps, a Peppol BIS V3 XML document can be thoroughly checked for syntax, format compliance, adherence to CEN TC434 and CIUS rules, and country-specific regulations, ensuring accurate and standardized electronic invoicing within the PEPPOL ecosystem.

UBL provides the standardized framework for expressing business data, while Peppol BIS V3 adds the necessary specifications and conventions for interoperability within the Peppol network. By aligning with UBL, Peppol ensures compatibility with a globally recognized standard, facilitating adoption and integration for businesses of all sizes.

In summary, the XML format used on the Peppol network combines the robustness of UBL 2.1 with the specificity of Peppol BIS V3, offering a powerful solution for electronic business communication and collaboration on a global scale.

Conclusion

In conclusion, the Peppol network represents a significant advancement in electronic document exchange, providing a standardized and secure platform. By leveraging innovative architecture and XML formats like UBL and Peppol BIS V3, Peppol promotes interoperability, transparency, and efficiency in commercial transactions. Its role in modernizing e-invoicing processes enhances trust and reliability in digital exchanges on a global scale.

Interesting links

• Peppol Website
• Belgium eInvoicing
• Search Peppol Directory
• Peppol BIS V3 Documentation Format
• UBL 2.1 Documentation
• Peppol Tools and Documentation