Integrate e-invoicing in your SaaS platform in minutes

As Belgium’s January 2026 e-invoicing mandate approaches, SaaS providers face a critical challenge: how to efficiently add compliant e-invoicing capabilities to their platforms without major development overhead. This is especially pressing for platforms whose tenants need to send invoices to their customers.

Challenge for SaaS Platforms

Many SaaS solutions—from accounting software to ERP systems, booking platforms to subscription management tools—generate PDF invoices for their users. However, with the upcoming mandate, these platforms must now support structured electronic invoices that comply with Peppol standards.

For SaaS owners and product managers, this presents several challenges:

  1. Development Resources: Building a compliant e-invoicing module from scratch requires significant investment
  2. Regulatory Complexity: Peppol standards and local requirements change frequently
  3. Multiple Integration Points: Connecting to various national access points and maintaining these connections
  4. User Experience: Maintaining simplicity for platform users who may not understand e-invoicing requirements

Integrating with Peppol Access Point

When talking to SaaS providers, we often hear that they want to integrate with the Peppol access point. This is a good option, but it requires a lot of effort to get right.

At e-invoice.be we offer a unique PDF to e-invoice service, amongst other options see below. This service allows you to convert your existing PDF invoices (which are still valid for all non-Belgian B2B businesses) to a valid UBL document and send it via Peppol.

1. Minimal Changes to Existing Systems

Most SaaS platforms already have robust PDF invoice generation. Your current invoice templates, business logic, and workflows can remain intact—all you need is an additional API call when an invoice is generated.

2. Avoiding UBL Complexity

Creating valid UBL (Universal Business Language) documents from scratch is notoriously challenging:

  • The Peppol BIS 3.0 specification includes hundreds of possible fields and complex business rules
  • Different countries have varying requirements and extensions
  • The XML schema is highly technical and requires specialized knowledge
  • Validation rules change over time, requiring constant maintenance

By relying on e-invoice.be to convert existing PDFs, you offload this complexity to a specialized service that stays current with the latest standards.

3. Rapid Time-to-Market

With PDF conversion, your e-invoicing solution can be implemented in days rather than the months typically required for a custom UBL generation system.

Integrtation example with e-invoice.be API

When your platform generates an invoice, it can simply add an API call to convert and send the invoice via Peppol:

How the Process Works:

The e-invoice.be API implementation follows a clear three-step process:

  1. PDF to UBL Conversion: Your existing PDF invoice is submitted to the API, which extracts the invoice data and converts it into a standardized UBL (Universal Business Language) document.

  2. Document Registration: The generated UBL document is registered in the e-invoice.be system, creating a permanent record and assigning a unique document ID for tracking and compliance purposes.

  3. Peppol Delivery: Using the document ID and Peppol network identifiers, the invoice is securely transmitted to your customer’s receiving system through the official Peppol network.

This streamlined workflow requires minimal code changes to your existing system and outsources all the complex conversion, validation, and delivery processes to the specialized e-invoice.be infrastructure.


async function sendInvoiceToPeppol(pdfInvoice, customerDetails) {
  // Step 1: Convert PDF to UBL
  const formData1 = new FormData();
  formData1.append('file', new Blob([pdfInvoice], { type: 'application/pdf' }), 'invoice.pdf');
  
  const pdfResponse = await fetch('https://api.e-invoice.be/api/documents/pdf', {
    method: 'POST',
    headers: {
      'Authorization': `Bearer ${API_KEY}`
    },
    body: formData1
  });
  
  const pdfResult = await pdfResponse.json();
  
  // Check if UBL document was successfully created
  if (!pdfResult.ubl_document) {
    throw new Error("Failed to extract sufficient details from PDF for UBL generation");
  }
  
  // Step 2: Create document from UBL
  const ublContent = Buffer.from(pdfResult.ubl_document, 'base64');
  const formData2 = new FormData();
  formData2.append('file', new Blob([ublContent], { type: 'application/xml' }), 'document.xml');
  
  const ublResponse = await fetch('https://api.e-invoice.be/api/documents/ubl', {
    method: 'POST',
    headers: {
      'Authorization': `Bearer ${API_KEY}`
    },
    body: formData2
  });
  
  const ublResult = await ublResponse.json();
  
  // Ensure we have a document ID
  if (!ublResult.id) {
    throw new Error("Failed to create document from UBL");
  }
  
  // Step 3: Send document via Peppol
  const sendPayload = {
    sender_peppol_scheme: '0208', // Peppol identifier scheme (0208 for Belgium VAT)
    sender_peppol_id: '0123456789',
    receiver_peppol_scheme: '0208',
    receiver_peppol_id: customerDetails.vatNumber
  };
  
  const sendResponse = await fetch(`https://api.e-invoice.be/api/documents/${ublResult.id}/send`, {
    method: 'POST',
    headers: {
      'Authorization': `Bearer ${API_KEY}`,
      'Content-Type': 'application/json'
    },
    body: JSON.stringify(sendPayload)
  });
  
  const sendResult = await sendResponse.json();
  
  // Store the document reference in your database
  await storeUblReference(invoiceId, ublResult.id);
  
  return sendResult;
}

Different integration options

At e-invoice.be, we understand that different SaaS providers have varying levels of technical resources and requirements. That’s why we offer multiple integration paths:

1. PDF Conversion (Simplest)

  • How it works: Send us your existing PDF invoices; we convert them to valid UBL
  • Best for: Quick implementation, minimal changes to existing systems
  • Time to market: Minutes

This is the option for which we showed the code example.

2. Simplified JSON Format (Intermediate)

  • How it works: Send invoice data in a straightforward JSON format; we convert to valid UBL
  • Best for: Platforms that have structured invoice data but want to avoid UBL complexity
  • Time to market: Hours

3. Direct UBL Creation (Advanced)

  • How it works: Create UBL documents directly within your platform
  • Best for: Enterprise platforms with dedicated resources and complex requirements
  • Time to market: Days

Most SaaS providers start with PDF conversion for its simplicity and speed, then potentially evolve their strategy over time.

SaaS-Friendly Pricing Model

Our pay-per-invoice pricing model is specifically designed to align with SaaS business models:

  • No setup fees - Start with zero upfront investment
  • No monthly subscriptions - Only pay for what you actually use
  • Volume discounts - Costs decrease as your e-invoicing volume grows
  • Transparent pricing - No hidden fees or unexpected charges
  • Multi-tenant friendly - Easy to distribute costs across your customer base

This model enables SaaS providers to start small, scale gradually, and pass costs through to customers in a predictable way. It eliminates the financial risk typically associated with adding new platform capabilities, making it easier to build e-invoicing costs into your existing pricing structure.

Key Benefits for SaaS Providers

By integrating with e-invoice.be’s API, SaaS providers gain:

  1. Rapid Compliance: Meet the 2026 deadline without extensive development
  2. Minimal Code Changes: Simple API integration that works alongside existing processes
  3. Future-Proofing: As regulations evolve, e-invoice.be handles the compliance updates
  4. White-Label Solution: Offer e-invoicing as a seamless part of your platform
  5. Competitive Advantage: Provide compliant e-invoicing before your competitors

Get Started Today

The January 2026 deadline may seem distant, but implementing and testing e-invoicing functionality takes time. By integrating with e-invoice.be now, you can:

  1. Test the solution thoroughly before the mandate
  2. Gradually roll out the feature to your users
  3. Position your platform as forward-thinking and compliance-ready

Visit https://e-invoice.be to learn more, or explore the full API documentation at https://api.e-invoice.be/api/docs to start planning your integration today.