nodejs

ZUGFeRD for Node.js: InvoiceXML API Examples

Node.js code samples for creating, validating, and extracting ZUGFeRD 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 ZUGFeRD 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 ZUGFeRD PDF/A-3 invoice with embedded EN 16931 XML	POST /v1/create/zugferd
validate.js	Validate a ZUGFeRD file against schematron rules	POST /v1/validate/zugferd
extract-json.js	Extract ZUGFeRD invoice data as JSON	POST /v1/extract/json
extract-xml.js	Extract the raw factur-x.xml from a ZUGFeRD PDF	POST /v1/extract/xml
ai-convert.js	(Experimental) Convert a plain PDF to ZUGFeRD with AI	POST /v1/transform/to/zugferd

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 ZUGFeRD 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/zugferd', {
    method: 'POST',
    headers: {
        'Content-Type': 'application/json',
        Authorization: 'Bearer ' + apiKey,
    },
    body: JSON.stringify(payload),
});

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

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

Full example: create.js | API reference

---

Validate a ZUGFeRD 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/zugferd', {
    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 ZUGFeRD data as JSON in Node.js

Useful for feeding ZUGFeRD 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 ZUGFeRD 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

---

(Experimental) Convert a plain PDF to ZUGFeRD with AI

Experimental feature. Human verification required before any production use.

Real-world PDF invoices are often messy: scanned at low quality, irregularly formatted, multi-page, or missing fields that EN 16931 requires. AI extraction can make subtle mistakes that automated validators may not catch: wrong tax category codes, transposed amounts, missing seller VAT identifiers, incorrect currency formatting.

Always review the output PDF before sending it to a customer or tax authority. See the AI conversion notes in the main README.

Full example: ai-convert.js | API reference

---

Framework integration

Express

Return a ZUGFeRD invoice from a route handler:

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

app.get('/invoices/:id/zugferd', async (req, res) => {
    const pdf = await createZugferd(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/zugferd')
    @Header('Content-Type', 'application/pdf')
    async download(@Param('id') id: string, @Res() res: Response) {
        const pdf = await this.zugferdService.create(id);
        res.setHeader('Content-Disposition', `attachment; filename="invoice-${id}.pdf"`);
        res.send(pdf);
    }
}

Next.js App Router

// app/api/invoices/[id]/zugferd/route.ts
export async function GET(req: Request, { params }: { params: { id: string } }) {
    const pdf = await createZugferd(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.

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Resources

• Get an InvoiceXML API key
• Create ZUGFeRD API reference
• Validate ZUGFeRD API reference
• Extract JSON API reference
• Extract XML API reference
• Transform to ZUGFeRD API reference
• Node.js fetch API documentation
• Main repository README