What Access Points do

An Access Point (AP) in the Peppol network is a certified piece of software, operated by a Service Provider, that allows organizations to send and receive electronic business documents—such as e-invoices, orders, and shipping notices—using a standardized syntax and a secure network under a legal framework. Access Points operate within what is called the four-corner model, where each party (sender and receiver) communicates only with their respective Access Points, which then transmit the documents across the Peppol network. This model enables interoperability and compliance without requiring direct integration between every trading partner, significantly reducing complexity for businesses and public institutions alike. The four-corner topology also introduces a model for unlimited scalability, very similar to how mobile phone networks are built.

Each Access Point must comply with strict technical specifications and governance rules outlined by OpenPeppol, including the use of structured document formats (such as UBL or EDIFACT) and secure protocols like AS4 and Transport Layer Security (TLS) AP-to-AP document exchange. These rules ensure a high level of security, interoperability and scalability for domestic and cross border exchange.

For example, the European Commission endorses the Peppol framework as part of its efforts to standardize eProcurement across EU member states, making Access Points an essential part of achieving e-invoicing compliance under the EU directive 2014/55/EU.
Rather than setting up and managing their own infrastructure, many businesses choose to use pre-accredited Access Point providers, which are already certified and connected to the network. This approach allows faster onboarding, reduced operational risk, and instant compliance with local and international requirements. In this context, Access Points are not just data pipelines—they are critical enablers of digital transformation in procurement and tax reporting across both public and private sectors.

Document Validation & Routing

In the Peppol network, document validation and routing are essential processes that ensure the safe and compliant exchange of electronic documents between organizations. When a sender submits a document, such as an invoice or purchase order, to their Access Point, the message undergoes a validation process to ensure it meets the technical and semantic rules defined by the Peppol BIS (Business Interoperability Specifications) and supported syntaxes like UBL (Universal Business Language). Validation checks include verifying the structure of the XML document, adherence to schemas, presence of required elements, and business rules relevant to the transaction type. This step is critical because it prevents the propagation of incorrect or non-compliant documents across the network, which could otherwise lead to errors, rejections, or regulatory issues.

After successful validation, the document is routed through the Peppol network using the Service Metadata Publisher (SMP) and the Service Metadata Locator (SML). The SMP provides metadata about recipients, including their capabilities and the specific document types they accept. The Access Point uses this metadata to determine the recipient's Access Point and securely deliver the message. The entire process is governed by the Peppol transport architecture, which defines how messages are exchanged using the AS4 protocol, ensuring encryption, non-repudiation, and reliable delivery.

This validation and routing mechanism allows Peppol to function as a decentralized but trusted network for eProcurement and eInvoicing. It eliminates the need for bilateral agreements between each sender and receiver and replaces them with a shared infrastructure based on standards and automation. As a result, organizations can reduce processing errors, ensure legal compliance across jurisdictions, and increase operational efficiency when participating in electronic document exchange through the Peppol network.

SMP for discoverability

Within the Peppol network, the Service Metadata Publisher (SMP) and Service Metadata Locator (SML) are foundational components that enable dynamic document routing and ensure that electronic messages reach the correct recipient in a secure and standardized manner. The SMP is a decentralized directory that contains information about each recipient's capabilities, such as which types of documents they can receive, the transport protocols they support, and which Access Point they are connected to. Each organization registered in Peppol has an SMP entry that acts like an address book entry, providing essential metadata required for proper delivery. This metadata includes the participant's identifier, supported document formats, and endpoint addresses. The official specifications and examples can be found on the Peppol documentation portal.

To locate the appropriate SMP entry for a recipient, the network relies on the Service Metadata Locator (SML), a centralized service that maps participant identifiers to the URLs of their respective SMPs. The SML uses the Domain Name System (DNS) to generate a unique domain for each participant, enabling secure and automated discovery of their metadata. When a sender initiates a document exchange, their Access Point queries the SML to find the correct SMP, retrieves the metadata, and uses that information to route the message accordingly.

This combination of distributed metadata (via SMP) and centralized lookup (via SML) allows the Peppol network to scale globally while maintaining interoperability and reliability. It removes the need for manual configuration or static address books, making it possible to dynamically onboard new recipients and adapt to changing document handling capabilities in real time. These components are central to the Peppol vision of an open, vendor-neutral, and cross-border eDelivery infrastructure, as outlined in OpenPeppol's transport architecture.