> For the complete documentation index, see [llms.txt](https://docs.cleartax.in/product-help-and-support/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.cleartax.in/product-help-and-support/for-large-businesses/cleartax-e-invoicing-belgium/introduction/peppol-4-corner-model.md). # Peppol '4 Corner' Model The Belgian mandate is built entirely on the Peppol network. Understanding Peppol is essential to understanding the ClearTax solution. Peppol (Pan-European Public Procurement Online) is not a single platform but a secure, open network designed to exchange electronic business documents, including e-invoices. It functions similarly to a telecommunications network: just as a customer on one phone network can call a customer on any other network, a business on the Peppol network can transact with any other business registered on the network, regardless of their software or service provider. This system operates on a 4-Corner Model: 1. **Corner 1: The Sender (Your business)** 2. **Corner 2: The Sender's Access Point (Your service provider, e.g., ClearTax)** 3. **Corner 3: The Receiver's Access Point (Your customer's service provider)** 4. **Corner 4: The Receiver (Your customer)** This decentralized model is fundamentally different from centralized government portal systems. For B2B transactions in Belgium, businesses do not upload invoices to a single government website. Instead, compliance is achieved by exchanging the structured invoices directly with trading partners through the secure Peppol network, using a certified Access Point. This makes the choice of an Access Point the most critical compliance decision for a Belgian business.