SDKs

e-invoice.be publishes SDKs for five languages. Each SDK is generated from the OpenAPI specification of the API and gives you typed requests, typed responses, automatic retries and error classes. You do not have to write HTTP calls. All SDKs call the single API host https://api.e-invoice.be. The API key selects the mode: a key of a sandbox company makes the SDK run in test mode, and a key of a production company sends documents on the Peppol network. See Test mode and sandbox companies.

Available SDKs

Language	Repository	Package	Minimum runtime	Release status
TypeScript and JavaScript	e-invoice-ts	`e-invoice-api` (npm)	Node.js 20 LTS, TypeScript 4.9	Version 1.x
Python	e-invoice-py	`e-invoice-api` (PyPI)	Python 3.9	Version 1.x
Ruby	e-invoice-rb	`e-invoice-api` (RubyGems)	Ruby 3.2.0	Version 0.x, the interface can change
PHP	e-invoice-php	`e-invoice-be/e-invoice` (Composer, from the repository)	PHP 8.1.0	Version 0.x, the interface can change
Java	e-invoice-java	`com.e_invoice.api:e-invoice-java`	Java 8	Alpha

The TypeScript SDK also runs in Deno 1.28.0 and later, Bun 1.0 and later, Cloudflare Workers and the Vercel Edge Runtime. The README of the repository has the full list.

Install an SDK

npm install e-invoice-api

pip install e-invoice-api

# Gemfile
gem "e-invoice-api", "~> 0.33.0"

{
  "repositories": [
    {
      "type": "vcs",
      "url": "git@github.com:e-invoice-be/e-invoice-php.git"
    }
  ],
  "require": {
    "e-invoice-be/e-invoice": "dev-main"
  }
}

<dependency>
  <groupId>com.e_invoice.api</groupId>
  <artifactId>e-invoice-java</artifactId>
  <version>0.1.0-alpha.12</version>
</dependency>

The Ruby and Java version numbers above are the versions in each README at the time of writing. Use the README of the repository to find the current version.

The PHP SDK is not on Packagist. Composer installs it from the GitHub repository, as the repositories entry in the sample shows.

The Java coordinates above are the coordinates in the README of the Java SDK. At the time of writing (2026-10-01), the artifact com.e_invoice.api:e-invoice-java is not yet on Maven Central: repo1.maven.org returns 404 for it. If your build cannot find the artifact, see the README of the repository for the current status.

Authenticate

Each SDK reads the API key from the environment variable E_INVOICE_API_KEY. Do not put the key in your source code.

export E_INVOICE_API_KEY="your-api-key"

To get an API key, see Authentication.

Validate, create and send a document

The samples do the same operations in each language:

Create a client and read the account of the API key (GET /api/me/).
Validate the invoice JSON (POST /api/validate/json).
Create the document (POST /api/documents/). The document is in the DRAFT state.
Send the document (POST /api/documents/{document_id}/send).

Validation is not a separate mandatory call. POST /api/documents/ rejects a payload that does not pass the same rules. Use POST /api/validate/json while you develop, because it returns all rule failures and the generated UBL.

The samples use the vendor E-INVOICE BV (BE1018265814). Replace vendor_name, vendor_tax_id and vendor_address with the data of your own company. A sandbox company has an assigned VAT number, which you can read from the account response.

import EInvoice from 'e-invoice-api';

// Reads the key from E_INVOICE_API_KEY
const client = new EInvoice();

const account = await client.me.retrieve();
console.log(account.name);

const invoice: EInvoice.DocumentCreateParams = {
  document_type: 'INVOICE',
  invoice_id: 'INV-2026-001',
  invoice_date: '2026-10-01',
  due_date: '2026-10-31',
  currency: 'EUR',
  vendor_name: 'E-INVOICE BV',
  vendor_tax_id: 'BE1018265814',
  vendor_address: 'Brusselsesteenweg 119/A, 1980 Zemst, Belgium',
  customer_name: 'OpenPeppol VZW',
  customer_tax_id: 'BE0848934496',
  customer_address: 'Robert Schumanplein 6 bus 5, 1040 Brussel, Belgium',
  items: [
    {
      description: 'Professional services',
      quantity: 10,
      unit: 'C62',
      unit_price: 100.0,
      amount: 1000.0,
      tax_rate: '21.00',
    },
  ],
};

const validation = await client.validate.validateJson(invoice);
if (!validation.is_valid) {
  console.error(validation.issues);
  process.exit(1);
}

const document = await client.documents.create(invoice);
console.log(document.id, document.state);

const sent = await client.documents.send(document.id);
console.log(sent.state);

from e_invoice_api import EInvoice

# Reads the key from E_INVOICE_API_KEY
client = EInvoice()

account = client.me.retrieve()
print(account.name)

invoice = {
    "document_type": "INVOICE",
    "invoice_id": "INV-2026-001",
    "invoice_date": "2026-10-01",
    "due_date": "2026-10-31",
    "currency": "EUR",
    "vendor_name": "E-INVOICE BV",
    "vendor_tax_id": "BE1018265814",
    "vendor_address": "Brusselsesteenweg 119/A, 1980 Zemst, BE",
    "customer_name": "OpenPeppol VZW",
    "customer_tax_id": "BE0848934496",
    "customer_address": "Robert Schumanplein 6 bus 5, 1040 Brussel, BE",
    "items": [
        {
            "description": "Professional services",
            "quantity": 10,
            "unit": "C62",
            "unit_price": 100.00,
            "amount": 1000.00,
            "tax_rate": "21.00",
        }
    ],
}

validation = client.validate.validate_json(**invoice)
if not validation.is_valid:
    print(validation.issues)
    raise SystemExit(1)

document = client.documents.create(**invoice)
print(document.id, document.state)

sent = client.documents.send(document.id)
print(sent.state)

require "bundler/setup"
require "date"
require "e_invoice_api"

# Reads the key from E_INVOICE_API_KEY
e_invoice = EInvoiceAPI::Client.new

account = e_invoice.me.retrieve
puts(account.name)

invoice = {
  document_type: :INVOICE,
  invoice_id: "INV-2026-001",
  invoice_date: Date.new(2026, 10, 1),
  due_date: Date.new(2026, 10, 31),
  currency: :EUR,
  vendor_name: "E-INVOICE BV",
  vendor_tax_id: "BE1018265814",
  vendor_address: "Brusselsesteenweg 119/A, 1980 Zemst, BE",
  customer_name: "OpenPeppol VZW",
  customer_tax_id: "BE0848934496",
  customer_address: "Robert Schumanplein 6 bus 5, 1040 Brussel, BE",
  items: [
    {
      description: "Professional services",
      quantity: 10,
      unit: :C62,
      unit_price: 100.00,
      amount: 1000.00,
      tax_rate: "21.00"
    }
  ]
}

validation = e_invoice.validate.validate_json(**invoice)
unless validation.is_valid
  puts(validation.issues)
  exit(1)
end

document = e_invoice.documents.create(**invoice)
puts(document.id, document.state)

sent = e_invoice.documents.send_(document.id)
puts(sent.state)

<?php

require __DIR__ . '/vendor/autoload.php';

use EInvoiceAPI\Client;

// Reads the key from E_INVOICE_API_KEY
$client = new Client();

$account = $client->me->retrieve();
echo $account->name, PHP_EOL;

$invoice = [
    'document_type' => 'INVOICE',
    'invoice_id' => 'INV-2026-001',
    'invoice_date' => '2026-10-01',
    'due_date' => '2026-10-31',
    'currency' => 'EUR',
    'vendor_name' => 'E-INVOICE BV',
    'vendor_tax_id' => 'BE1018265814',
    'vendor_address' => 'Brusselsesteenweg 119/A, 1980 Zemst, Belgium',
    'customer_name' => 'OpenPeppol VZW',
    'customer_tax_id' => 'BE0848934496',
    'customer_address' => 'Robert Schumanplein 6 bus 5, 1040 Brussel, Belgium',
    'items' => [
        [
            'description' => 'Professional services',
            'quantity' => 10,
            'unit' => 'C62',
            'unit_price' => 100.00,
            'amount' => 1000.00,
            'tax_rate' => '21.00',
        ],
    ],
];

$validation = $client->validate->validateJson($invoice);
if (!$validation->is_valid) {
    var_dump($validation->issues);
    exit(1);
}

$document = $client->documents->create($invoice);
echo $document->id, PHP_EOL;

$sent = $client->documents->send($document->id, []);
var_dump($sent->state);

import com.e_invoice.api.client.EInvoiceClient;
import com.e_invoice.api.client.okhttp.EInvoiceOkHttpClient;
import com.e_invoice.api.models.documents.CurrencyCode;
import com.e_invoice.api.models.documents.DocumentCreate;
import com.e_invoice.api.models.documents.DocumentResponse;
import com.e_invoice.api.models.documents.DocumentType;
import com.e_invoice.api.models.documents.UnitOfMeasureCode;
import com.e_invoice.api.models.validate.UblDocumentValidation;
import java.time.LocalDate;

public class SendInvoice {
    public static void main(String[] args) {
        // Reads the key from E_INVOICE_API_KEY
        EInvoiceClient client = EInvoiceOkHttpClient.fromEnv();

        DocumentCreate invoice = DocumentCreate.builder()
            .documentType(DocumentType.INVOICE)
            .invoiceId("INV-2026-001")
            .invoiceDate(LocalDate.of(2026, 10, 1))
            .dueDate(LocalDate.of(2026, 10, 31))
            .currency(CurrencyCode.EUR)
            .vendorName("E-INVOICE BV")
            .vendorTaxId("BE1018265814")
            .vendorAddress("Brusselsesteenweg 119/A, 1980 Zemst, BE")
            .customerName("OpenPeppol VZW")
            .customerTaxId("BE0848934496")
            .customerAddress("Robert Schumanplein 6 bus 5, 1040 Brussel, BE")
            .addItem(DocumentCreate.Item.builder()
                .description("Professional services")
                .quantity(10.0)
                .unit(UnitOfMeasureCode.C62)
                .unitPrice(100.00)
                .amount(1000.00)
                .taxRate("21.00")
                .build())
            .build();

        UblDocumentValidation validation = client.validate().validateJson(invoice);
        if (!validation.isValid()) {
            System.err.println(validation.issues());
            System.exit(1);
        }

        DocumentResponse document = client.documents().create(invoice);
        System.out.println(document.id());

        DocumentResponse sent = client.documents().send(document.id());
        System.out.println(sent.state());
    }
}

The Java SDK is an alpha release. It does not have the account resource (GET /api/me/), thus the Java sample starts with the validation step.

The send call accepts the optional routing parameters sender_peppol_scheme, sender_peppol_id, receiver_peppol_scheme, receiver_peppol_id and email. In Java, the names are in camel case in DocumentSendParams. See Create e-invoices for when to set them. With a sandbox company, the send call does not use the Peppol network. See Test mode and sandbox companies.

Method names for each SDK

Operation	TypeScript	Python	Ruby	PHP	Java
Get account	`client.me.retrieve()`	`client.me.retrieve()`	`me.retrieve`	`$client->me->retrieve()`	Not available
Validate JSON	`client.validate.validateJson()`	`client.validate.validate_json()`	`validate.validate_json`	`$client->validate->validateJson()`	`client.validate().validateJson()`
Create document	`client.documents.create()`	`client.documents.create()`	`documents.create`	`$client->documents->create()`	`client.documents().create()`
Send document	`client.documents.send()`	`client.documents.send()`	`documents.send_`	`$client->documents->send()`	`client.documents().send()`

In Ruby, the send method has the name send_ with an underscore at the end, because send is a method of each Ruby object.

The TypeScript and Python repositories have a file api.md with the full list of methods.

Versions and the OpenAPI specification

The API has one OpenAPI specification, which is version 1.1.0 at this time. Each SDK is generated from this specification, but each SDK has its own version number. An SDK version number does not agree with the version number of the specification.

The TypeScript, Python and Java SDKs follow semantic versioning, with the exceptions that each README gives.
The Ruby and PHP SDKs have major version 0. Their README states that the interface can change at any time.
A new endpoint can be in the API before it is in an SDK. The API reference always shows the current API. Each README shows how to call an endpoint that the SDK does not have yet.

Report a problem

Report a problem with an SDK in the issues of its repository:

Next Steps

peppol CLI

Validate, create and send documents from the command line

Create e-invoices

Learn the fields of an invoice

Errors and troubleshooting

Handle the errors that the API returns

API reference

See all endpoints and schemas

Getting started

Send documents

Receive and manage

Other input formats

Integrate

SDKs and tools

Resellers

Reference

Available SDKs

Install an SDK

Authenticate

Validate, create and send a document

Method names for each SDK

Versions and the OpenAPI specification

Report a problem

Next Steps

peppol CLI

Create e-invoices

Errors and troubleshooting

API reference

​Available SDKs

​Install an SDK

​Authenticate

​Validate, create and send a document

​Method names for each SDK

​Versions and the OpenAPI specification

​Report a problem

​Next Steps

peppol CLI

Create e-invoices

Errors and troubleshooting

API reference

Available SDKs

Install an SDK

Authenticate

Validate, create and send a document

Method names for each SDK

Versions and the OpenAPI specification

Report a problem

Next Steps