Authentication

Overview

The e-invoice.be API uses Bearer Token Authentication for all endpoints. You’ll need to include your API key in the Authorization header of every request.

Quick Start for New Users

If you’re just getting started:

Use the production API: https://api.e-invoice.be
Create a sandbox company: In app.e-invoice.be, click Create sandbox company to get a test-mode company and its own API key
Start developing: A sandbox company prevents real Peppol transmission while you build your integration

For most users, you only need to know about api.e-invoice.be and test mode.

Understanding the Setup

What API Should I Use?

Answer: Use https://api.e-invoice.be - This single API works for both development and live transactions.

How Do I Test Without Sending Real Invoices?

Answer: Create a sandbox company. A sandbox company runs in test mode: documents are emailed instead of being sent via Peppol. This lets you:

Test your integration safely
Verify invoice data and UBL generation
See exactly what would be sent via Peppol

Create one from app.e-invoice.be — see Test Mode for the full walkthrough.

API Host

Production API: `api.e-invoice.be`

Base URL: https://api.e-invoice.be This is the only API host you need:

✅ For development: With test mode enabled
✅ For production: With test mode disabled
✅ Stable features: Well-tested, production-ready
✅ Standard rate limits: Suitable for most applications

Use https://api.e-invoice.be for everything. Test mode determines whether documents go out over Peppol, not the base URL.

Test Mode Explained

Test mode is delivered through a sandbox company — a dedicated company that changes how documents are transmitted:

Company	What Happens When You Send a Document
Sandbox (for development)	Email sent with UBL XML - no Peppol transmission
Regular (for production)	Document sent via Peppol network to recipient

Key Points About Test Mode

It’s determined by the company you authenticate as, not by which base URL you use
A sandbox company has its own API key, separate from your live company’s key
A sandbox company cannot be converted to a live one — create a separate regular company to go live
Everything else works the same (validation, webhooks, API endpoints, etc.)

Create a sandbox company from app.e-invoice.be. See Test Mode for details.

Getting Your API Key

If you haven’t already obtained your API key:

Log in to app.e-invoice.be
Go to Settings → API Keys
Click Create API Key
Copy and securely store your key

Your API key is sensitive. Never share it publicly, commit it to version control, or expose it in client-side code.

Making Authenticated Requests

Include your API key in the Authorization header with the Bearer prefix:

curl -X GET "https://api.e-invoice.be/api/me/" \
     -H "Authorization: Bearer YOUR_API_KEY"

Request Format

Authorization: Bearer YOUR_API_KEY

Replace YOUR_API_KEY with your actual API key.

The same API key works whether or not test mode is enabled on your account.

Code Examples

const axios = require('axios');

// Most users should use the production API
const BASE_URL = 'https://api.e-invoice.be';

const api = axios.create({
  baseURL: BASE_URL,
  headers: {
    'Authorization': `Bearer ${process.env.E_INVOICE_API_KEY}`,
    'Content-Type': 'application/json'
  }
});

// Example: Get account info
async function getAccountInfo() {
  try {
    const response = await api.get('/api/me/');
    console.log(response.data);
  } catch (error) {
    console.error('Error:', error.response?.data);
  }
}

import os
import requests

API_KEY = os.environ.get('E_INVOICE_API_KEY')

# Most users should use the production API
BASE_URL = 'https://api.e-invoice.be'

headers = {
    'Authorization': f'Bearer {API_KEY}',
    'Content-Type': 'application/json'
}

# Example: Get account info
response = requests.get(f'{BASE_URL}/api/me/', headers=headers)
print(response.json())

<?php
$apiKey = getenv('E_INVOICE_API_KEY');

// Most users should use the production API
$baseUrl = 'https://api.e-invoice.be';

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $baseUrl . '/api/me/');
curl_setopt($ch, CURLOPT_HTTPHEADER, [
    'Authorization: Bearer ' . $apiKey,
    'Content-Type: application/json'
]);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

$response = curl_exec($ch);
curl_close($ch);

$data = json_decode($response, true);
print_r($data);
?>

package main

import (
    "fmt"
    "io"
    "net/http"
    "os"
)

func main() {
    apiKey := os.Getenv("E_INVOICE_API_KEY")

    // Most users should use the production API
    baseURL := "https://api.e-invoice.be"

    client := &http.Client{}
    req, _ := http.NewRequest("GET", baseURL+"/api/me/", nil)
    req.Header.Set("Authorization", "Bearer "+apiKey)
    req.Header.Set("Content-Type", "application/json")

    resp, err := client.Do(req)
    if err != nil {
        panic(err)
    }
    defer resp.Body.Close()

    body, _ := io.ReadAll(resp.Body)
    fmt.Println(string(body))
}

Best Practices

Store API Keys Securely

Use environment variables or secure credential management systems:

# .env file (add to .gitignore!)
E_INVOICE_API_KEY=your_api_key_here

// Load from environment
require('dotenv').config();
const apiKey = process.env.E_INVOICE_API_KEY;

Never Hardcode Keys

❌ Don’t do this:

const apiKey = 'sk_live_abc123...'; // Never hardcode!
const baseUrl = 'https://api.e-invoice.be'; // Don't hardcode this either!

✅ Do this instead:

const apiKey = process.env.E_INVOICE_API_KEY;
const baseUrl = process.env.E_INVOICE_BASE_URL || 'https://api.e-invoice.be';

Development Workflow

Create a sandbox company in app.e-invoice.be and use its API key
Use the production API (api.e-invoice.be) for development
Switch to your live company’s API key when you’re ready to go live

# .env (same base URL; swap the API key per environment)
E_INVOICE_API_KEY=your_api_key
E_INVOICE_BASE_URL=https://api.e-invoice.be

You don’t need to change your base URL or code when switching from development to production - just use your live company’s API key and documents will be sent via Peppol instead of email. Learn more about test mode →

Rotate Keys Regularly

For security best practices:

Generate a new API key in your dashboard
Update your applications to use the new key
Delete the old key once migration is complete

Use Multiple API Keys

Create separate API keys for:

Sandbox companies (test mode) and real companies (production)
Different applications or services
Different team members or departments
Programmatic access vs. manual testing

This allows you to rotate or revoke keys without affecting all systems.

Error Responses

401 Unauthorized

If authentication fails, you’ll receive a 401 error:

{
  "detail": "Invalid authentication"
}

Common causes:

Missing Authorization header
Invalid API key format
Expired or revoked API key
Typo in API key
Using a sandbox company’s API key for production sends (or vice versa)

Troubleshooting

Verify the header format: Ensure you’re using Bearer YOUR_API_KEY
Check for whitespace: Trim any extra spaces from your API key
Confirm the workspace: Make sure you’re using the correct API key (sandbox company vs. real company)
Test with curl: Verify your key works with a simple curl command

curl -X GET "https://api.e-invoice.be/api/me/" \
     -H "Authorization: Bearer YOUR_API_KEY" \
     -v

Testing Your Authentication

Use the /api/me/ endpoint to verify your authentication is working:

curl -X GET "https://api.e-invoice.be/api/me/" \
     -H "Authorization: Bearer YOUR_API_KEY"

Successful response:

{
  "name": "Your Company",
  "company_name": "Your Company BV",
  "company_number": "0123456789",
  "company_country": "Belgium",
  "peppol_ids": ["0208:0123456789"],
  "plan": "starter",
  "credit_balance": 100
}

If you see this response, your authentication is working correctly!

Next Steps

Create Your First Invoice

Learn how to create and send e-invoices

Validate During Development

Test your invoice data before sending

Getting started

Core guides

Alternative formats

Integration

Partners

Overview

Quick Start for New Users

Understanding the Setup

What API Should I Use?

How Do I Test Without Sending Real Invoices?

API Host

Production API: `api.e-invoice.be`

Test Mode Explained

Key Points About Test Mode

Getting Your API Key

Making Authenticated Requests

Request Format

Code Examples

Best Practices

Store API Keys Securely

Never Hardcode Keys

Development Workflow

Rotate Keys Regularly

Use Multiple API Keys

Error Responses

401 Unauthorized

Troubleshooting

Testing Your Authentication

Next Steps

Create Your First Invoice

Validate During Development

​Overview

​Quick Start for New Users

​Understanding the Setup

​What API Should I Use?

​How Do I Test Without Sending Real Invoices?

​API Host

​Production API: api.e-invoice.be

​Test Mode Explained

​Key Points About Test Mode

​Getting Your API Key

​Making Authenticated Requests

​Request Format

​Code Examples

​Best Practices

​Store API Keys Securely

​Never Hardcode Keys

​Development Workflow

​Rotate Keys Regularly

​Use Multiple API Keys

​Error Responses

​401 Unauthorized

​Troubleshooting

​Testing Your Authentication

​Next Steps

Create Your First Invoice

Validate During Development

Overview

Quick Start for New Users

Understanding the Setup

What API Should I Use?

How Do I Test Without Sending Real Invoices?

API Host

Production API: `api.e-invoice.be`

Test Mode Explained

Key Points About Test Mode

Getting Your API Key

Making Authenticated Requests

Request Format

Code Examples

Best Practices

Store API Keys Securely

Never Hardcode Keys

Development Workflow

Rotate Keys Regularly

Use Multiple API Keys

Error Responses

401 Unauthorized

Troubleshooting

Testing Your Authentication

Next Steps