nodejs

Factur-X for Node.js: InvoiceXML API Examples

Node.js code samples for creating, validating, and extracting Factur-X electronic invoices using the InvoiceXML API. Compatible with Node.js 18 and later (native fetch and FormData). Runs in Express, NestJS, Fastify, Koa, Hapi, Next.js API routes, AWS Lambda, Cloudflare Workers, Vercel Functions, or plain scripts. Zero npm dependencies.

For background on the Factur-X standard itself (what it is, profiles, legal status), see the main repository README.

Get your API key

Every example in this folder calls the InvoiceXML REST API. Sign up and generate a free API key here:

→ https://www.invoicexml.com/account/authentication

Pass it as a Bearer token on every request:

Authorization: Bearer YOUR_API_KEY

Important: set apiKey in the examples to the raw key only, without the Bearer prefix. If your account page shows the full header value (e.g. Bearer ixml_a1b2c3...), copy only the part after Bearer . The code adds the prefix itself when building the Authorization header.

Requirements

• Node.js 18.0 or later (current LTS recommended: Node 20 or 22)
• No npm packages, no package.json needed

The examples use Node's built-in global fetch, FormData, Blob, and Buffer. These have been stable in Node 18+. If you must support Node 16 or older, polyfill fetch with node-fetch and FormData with form-data.

Files in this folder

File	Operation	API endpoint
create.js	Build a Factur-X PDF/A-3 invoice with embedded EN 16931 XML	POST /v1/create/facturx
validate.js	Validate a Factur-X file against schematron rules	POST /v1/validate/facturx
extract-json.js	Extract Factur-X invoice data as JSON	POST /v1/extract/json
extract-xml.js	Extract the raw factur-x.xml from a Factur-X PDF	POST /v1/extract/xml
embed.js	Embed your own CII XML into your own PDF as a Factur-X PDF/A-3	POST /v1/embed/facturx

Each file is standalone and runnable with node create.js. Open the file, replace YOUR_API_KEY with your real key, and execute.

Note on the snippets below: they are excerpts from those files and assume apiKey (and fs) are already defined. They also use await at the top level, which is not valid in a plain CommonJS script; the full files wrap the calls in an async IIFE. When in doubt, copy the complete file.

---

Create a Factur-X invoice in Node.js

const payload = {
    invoice: {
        invoiceNumber: 'MIN-001',
        issueDate:     '2026-05-18',
        currency:      'EUR',
        seller: {
            name:              'Acme',
            vatIdentifier:     'DE123456789',
            legalRegistration: { identifier: 'HRB 12345' },
            postalAddress: { line1: 'Hauptstraße 12', city: 'Berlin', postCode: '10115', country: 'DE' },
        },
        buyer: {
            name: 'Globex SAS',
            postalAddress: { line1: '15 rue de Rivoli', city: 'Paris', postCode: '75001', country: 'FR' },
        },
        paymentDetails: { paymentAccountIdentifier: 'DE89370400440532013000' },
        lines: [{
            quantity:       10,
            priceDetails:   { netPrice: 150.00 },
            vatInformation: { rate: 19.00 },
            item:           { name: 'Senior consulting' },
        }],
    },
};

const response = await fetch('https://api.invoicexml.com/v1/create/facturx', {
    method: 'POST',
    headers: {
        'Content-Type': 'application/json',
        Authorization: 'Bearer ' + apiKey,
    },
    body: JSON.stringify(payload),
});

const buffer = Buffer.from(await response.arrayBuffer());
fs.writeFileSync('invoice-facturx.pdf', buffer);

The response is a binary PDF/A-3 file with the Factur-X XML already embedded.

Full example: create.js | API reference

---

Validate a Factur-X file in Node.js

const fs = require('fs');

const form = new FormData();
form.append('file', new Blob([fs.readFileSync('invoice.pdf')], { type: 'application/pdf' }), 'invoice.pdf');
form.append('version', '2.3.2');
form.append('profile', 'extended');

const response = await fetch('https://api.invoicexml.com/v1/validate/facturx', {
    method: 'POST',
    headers: { Authorization: 'Bearer ' + apiKey },
    body: form,
});

console.log(await response.text());

Returns a JSON validation report listing any schematron rule failures (EN 16931 BR-* and BR-CO-* rules).

Full example: validate.js | API reference

---

Extract Factur-X data as JSON in Node.js

Useful for feeding Factur-X invoices into Express controllers, message queues, or any pipeline that prefers JSON over XML.

const fs = require('fs');

const form = new FormData();
form.append('file', new Blob([fs.readFileSync('invoice.pdf')], { type: 'application/pdf' }), 'invoice.pdf');

const response = await fetch('https://api.invoicexml.com/v1/extract/json', {
    method: 'POST',
    headers: { Authorization: 'Bearer ' + apiKey },
    body: form,
});

const { invoice } = await response.json();
// The invoice document sits under the "invoice" key of the response.
console.log(invoice.seller.name, invoice.totals.grandTotalAmount);

Full example: extract-json.js | API reference | Sample response

---

Extract embedded XML from a Factur-X PDF in Node.js

Returns the raw factur-x.xml payload (UN/CEFACT Cross-Industry Invoice syntax). Use this when you need the structured XML to feed an existing UBL or CII pipeline, EDI partner, or archival system.

Full example: extract-xml.js | API reference

---

Embed your own XML into your own PDF

When your service already renders the invoice PDF and already produces the EN 16931 XML, post both files and the API keeps your visual layer exactly as designed, promotes the container to PDF/A-3, and attaches the XML as factur-x.xml with the correct AFRelationship and XMP metadata.

const form = new FormData();
form.append('pdf', new Blob([fs.readFileSync('invoice.pdf')], { type: 'application/pdf' }), 'invoice.pdf');
form.append('xml', new Blob([fs.readFileSync('factur-x.xml')], { type: 'application/xml' }), 'factur-x.xml');
form.append('skipValidation', 'false');

const response = await fetch('https://api.invoicexml.com/v1/embed/facturx', {
    method: 'POST',
    headers: { Authorization: `Bearer ${apiKey}` },
    body: form,
});

fs.writeFileSync('invoice-facturx.pdf', Buffer.from(await response.arrayBuffer()));

The XML runs through the complete /v1/validate/facturx rule set before anything is embedded, so a non-compliant invoice never leaves the API: fatal findings come back as a 400 with errorCode 4001 and the full finding list. Set skipValidation to true for packaging-only mode, where the structural checks (CII root element, official BT-24 profile URN, profile XSD) still apply but the business rules are skipped.

Only UN/CEFACT CII XML is accepted. If your invoice is UBL, convert it first with POST /v1/convert/ubl/to/cii. For the German packaging conventions, call /v1/embed/zugferd instead, same request shape.

Full example: embed.js | API reference

---

Framework integration

Express

Return a Factur-X invoice from a route handler:

const express = require('express');
const app = express();

app.get('/invoices/:id/facturx', async (req, res) => {
    const pdf = await createFacturX(req.params.id);
    res.setHeader('Content-Type', 'application/pdf');
    res.setHeader('Content-Disposition', `attachment; filename="invoice-${req.params.id}.pdf"`);
    res.send(pdf);
});

Store the API key in process.env.INVOICEXML_API_KEY and read it from dotenv or your platform's secret manager.

NestJS

@Controller('invoices')
export class InvoiceController {
    @Get(':id/facturx')
    @Header('Content-Type', 'application/pdf')
    async download(@Param('id') id: string, @Res() res: Response) {
        const pdf = await this.facturXService.create(id);
        res.setHeader('Content-Disposition', `attachment; filename="invoice-${id}.pdf"`);
        res.send(pdf);
    }
}

Next.js App Router

// app/api/invoices/[id]/facturx/route.ts
export async function GET(req: Request, { params }: { params: { id: string } }) {
    const pdf = await createFacturX(params.id);
    return new Response(pdf, {
        headers: {
            'Content-Type': 'application/pdf',
            'Content-Disposition': `attachment; filename="invoice-${params.id}.pdf"`,
        },
    });
}

Cloudflare Workers and Vercel Edge

The examples run on Workers and Edge runtimes unchanged because fetch and FormData are part of the runtime. Replace fs.readFileSync with an await request.arrayBuffer() from the inbound request and the same pattern works in serverless environments.

AWS Lambda (Node.js 18+)

Lambda's Node.js 18+ runtime provides native fetch and FormData, so the examples run as-is.

---

Common issues

• fetch is not defined: you are running Node 16 or older. Upgrade to Node 18+ (current LTS), or polyfill with npm install node-fetch form-data and import accordingly.
• HTTP 401 Unauthorized: API key missing or invalid. Generate one at invoicexml.com/account/authentication and confirm you are sending Authorization: Bearer YOUR_API_KEY. A frequent cause: setting apiKey to the whole Bearer xxx value, which sends Bearer Bearer xxx. Set the raw key only.
• HTTP 400 Bad Request on Create: a required field is missing or malformed. Frequent causes: IssueDate not in ISO format (YYYY-MM-DD), Currency not in ISO 4217 (EUR, USD), country codes not in ISO 3166-1 alpha-2 (DE, FR).
• ESM vs CommonJS: the examples use CommonJS (require). For ESM (.mjs extension or "type": "module" in package.json), swap require('fs') for import fs from 'node:fs' and you can use top-level await without the IIFE wrapper.
• Relative file paths: fs.readFileSync('invoice.pdf') resolves from the current working directory, not the script file. Use __dirname (CommonJS) or import.meta.dirname (ESM, Node 20.11+) for absolute paths.
• Schematron BR-CO- failures on Validate*: line totals do not match the header total, or tax category and tax percentage are inconsistent. Recompute totals before posting.

---

Resources

• Get an InvoiceXML API key
• Create Factur-X API reference
• Validate Factur-X API reference
• Extract JSON API reference
• Extract XML API reference
• Embed into Factur-X API reference
• Node.js fetch API documentation
• Main repository README