Name	Name	Last commit message	Last commit date
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create.php	create.php
extract-json.php	extract-json.php
readme.md	readme.md
render.php	render.php
validate.php	validate.php

XRechnung for PHP: InvoiceXML API Examples

PHP code samples for creating, validating, and parsing XRechnung electronic invoices using the InvoiceXML API. Compatible with PHP 7.0+ (PHP 8.x recommended), works in plain scripts, Laravel, Symfony, WordPress, WooCommerce, Drupal, Magento, or any other PHP framework. Zero Composer dependencies: uses PHP's built-in cURL extension.

For background on the XRechnung standard itself (what it is, the Leitweg-ID, 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

PHP 7.0 or later (PHP 8.2+ recommended)
The cURL extension (php-curl), bundled with most PHP installations by default
No Composer, no external libraries

These examples use the built-in curl_* functions and CURLFile (available since PHP 5.5), so they run on essentially any modern PHP install without composer install.

Files in this folder

File	Operation	API endpoint
`create.php`	Build an XRechnung 3.0 XML invoice	`POST /v1/create/xrechnung`
`validate.php`	Validate an XRechnung file against the KoSIT rules	`POST /v1/validate/xrechnung`
`extract-json.php`	Parse an XRechnung XML into JSON	`POST /v1/extract/json`
`ai-convert.php`	(Experimental) Convert a plain PDF to XRechnung with AI	`POST /v1/transform/to/xrechnung`
`render.php`	Render XRechnung XML into a human-readable PDF	`POST /v1/render/xrechnung/to/pdf`

Each file is standalone and runnable with php create.php. 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 is already defined. When in doubt, copy the complete file.

Create an XRechnung invoice in PHP

$payload = [
    'invoice' => [
        'invoiceNumber' => 'XR-2026-001',
        'issueDate'     => '2026-05-18',
        'currency'      => 'EUR',
        'buyerReference' => '991-12345-67',
        'seller' => [
            'name'              => 'Acme GmbH',
            'vatIdentifier'     => 'DE123456789',
            'legalRegistration' => ['identifier' => 'HRB 12345'],
            'postalAddress'     => ['line1' => 'Hauptstraße 12', 'city' => 'Berlin', 'postCode' => '10115', 'country' => 'DE'],
            'contact'           => ['name' => 'Max Mustermann', 'phone' => '+49 30 12345678', 'email' => 'billing@acme.de'],
            'electronicAddress' => ['identifier' => 'DE123456789', 'schemeId' => '9930'],
        ],
        'buyer' => [
            'name'              => 'Bundesamt für Musterverwaltung',
            'postalAddress'     => ['line1' => 'Behördenstraße 5', 'city' => 'Bonn', 'postCode' => '53113', 'country' => 'DE'],
            'electronicAddress' => ['identifier' => '991-12345-67', 'schemeId' => '0204'],
        ],
        'paymentDetails' => ['paymentAccountIdentifier' => 'DE89370400440532013000'],
        'lines' => [[
            'quantity'       => 10,
            'priceDetails'   => ['netPrice' => 150.00],
            'vatInformation' => ['rate' => 19.00],
            'item'           => ['name' => 'Senior consulting'],
        ]],
    ],
    'options' => ['syntax' => 'ubl'],
];

$ch = curl_init('https://api.invoicexml.com/v1/create/xrechnung');
curl_setopt_array($ch, [
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_POST           => true,
    CURLOPT_POSTFIELDS     => json_encode($payload),
    CURLOPT_HTTPHEADER     => [
        'Content-Type: application/json',
        'Authorization: Bearer ' . $apiKey,
    ],
]);
$xml = curl_exec($ch);
file_put_contents('invoice-xrechnung.xml', $xml);

buyerReference carries the Leitweg-ID (BT-10), and the seller contact and electronicAddress groups are what the XRechnung CIUS requires on top of plain EN 16931. Omit any of them and the API returns a 400 naming the BR-DE-* rule you missed.

The response is the XRechnung 3.0 XML document, validated against the KoSIT rules before delivery.

Full example: create.php | API reference

Validate an XRechnung file in PHP

$ch = curl_init('https://api.invoicexml.com/v1/validate/xrechnung');
curl_setopt_array($ch, [
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_POST           => true,
    CURLOPT_POSTFIELDS     => [
        'file' => new CURLFile('invoice.xml', 'application/xml'),
    ],
    CURLOPT_HTTPHEADER     => ['Authorization: Bearer ' . $apiKey],
]);
$report = curl_exec($ch);
echo $report;

Returns a JSON validation report listing any rule failures (EN 16931 BR-* and BR-CO-, plus the German BR-DE- rules).

Full example: validate.php | API reference

Extract XRechnung data as JSON in PHP

Useful for feeding XRechnung invoices into REST APIs, ERPs, accounting systems, or any pipeline that prefers JSON over XML.

$ch = curl_init('https://api.invoicexml.com/v1/extract/json');
curl_setopt_array($ch, [
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_POST           => true,
    CURLOPT_POSTFIELDS     => ['file' => new CURLFile('invoice.xml', 'application/xml')],
    CURLOPT_HTTPHEADER     => ['Authorization: Bearer ' . $apiKey],
]);
$json = curl_exec($ch);
$data = json_decode($json, true);
// The invoice document sits under the "invoice" key of the response.
echo $data['invoice']['seller']['name'];

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

(Experimental) Convert a plain PDF to XRechnung 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 before submitting it to a public authority. See the AI conversion notes in the main README.

The endpoint takes the PDF plus a buyerReference form field: the Leitweg-ID cannot be inferred from the source document, so you must supply it.

$ch = curl_init('https://api.invoicexml.com/v1/transform/to/xrechnung');
curl_setopt_array($ch, [
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_POST           => true,
    CURLOPT_POSTFIELDS     => [
        'file'           => new CURLFile('plain-invoice.pdf', 'application/pdf'),
        'buyerReference' => '991-12345-67',
    ],
    CURLOPT_HTTPHEADER     => ['Authorization: Bearer ' . $apiKey],
]);
$xml = curl_exec($ch);
file_put_contents('converted-xrechnung.xml', $xml);

Full example: ai-convert.php | API reference

Render XRechnung as a readable PDF in PHP

XRechnung has no visual layer: the XML is the invoice, which is fine for machines and useless for the person in accounts payable who wants to read it. This endpoint renders the XML into a formatted PDF preview, auto-detecting whether the file is CII or UBL syntax. The PDF is for reading only; the XML file remains the authoritative invoice for compliance and tax purposes.

$ch = curl_init('https://api.invoicexml.com/v1/render/xrechnung/to/pdf');
curl_setopt_array($ch, [
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_POST           => true,
    CURLOPT_POSTFIELDS     => [
        'file'     => new CURLFile('invoice.xml', 'application/xml'),
        'language' => 'de',   // en, de, or fr
    ],
    CURLOPT_HTTPHEADER     => ['Authorization: Bearer ' . $apiKey],
]);
$pdf = curl_exec($ch);
file_put_contents('invoice-preview.pdf', $pdf);

Full example: render.php | API reference

Framework integration

Laravel

Return an XRechnung invoice from a controller or route closure:

use Illuminate\Support\Facades\Route;

Route::get('/invoices/{id}/xrechnung', function ($id) {
    $pdf = app(XRechnungService::class)->create($id);
    return response($pdf, 200, [
        'Content-Type'        => 'application/pdf',
        'Content-Disposition' => "attachment; filename=\"invoice-{$id}.pdf\"",
    ]);
});

Store the API key in config/services.php and read it via config('services.invoicexml.key').

Symfony

use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\Routing\Annotation\Route;

class InvoiceController
{
    #[Route('/invoices/{id}/xrechnung', name: 'xrechnung_download')]
    public function download(int $id): Response
    {
        $pdf = $this->xrechnungService->create($id);
        return new Response($pdf, 200, [
            'Content-Type'        => 'application/pdf',
            'Content-Disposition' => "attachment; filename=\"invoice-{$id}.pdf\"",
        ]);
    }
}

WordPress and WooCommerce

Hook into WooCommerce order lifecycle events to generate XRechnung invoices automatically:

add_action('woocommerce_order_status_completed', function ($order_id) {
    $order = wc_get_order($order_id);
    $pdf = create_xrechnung_from_order($order);
    file_put_contents(WP_CONTENT_DIR . "/invoices/{$order_id}.pdf", $pdf);
});

The same pattern works in Magento, Drupal Commerce, and PrestaShop.

Common issues

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).
Class "CURLFile" not found: PHP cURL extension is missing. Install with apt-get install php-curl (Debian/Ubuntu), yum install php-curl (RHEL), or enable the extension in php.ini.
SSL certificate problem errors: the server's CA bundle is out of date. Update OpenSSL on the host, or set CURLOPT_CAINFO to a current cacert.pem from curl.se/ca/.
BR-DE- failures on Validate*: an XRechnung-specific field is missing. The most common are BR-DE-15 (no Leitweg-ID in buyerReference), BR-DE-2 (no seller contact group), and BR-DE-1 (no seller electronic address).

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readme.md

XRechnung for PHP: InvoiceXML API Examples

Get your API key

Requirements

Files in this folder

Create an XRechnung invoice in PHP

Validate an XRechnung file in PHP

Extract XRechnung data as JSON in PHP

(Experimental) Convert a plain PDF to XRechnung with AI

Render XRechnung as a readable PDF in PHP

Framework integration

Laravel

Symfony

WordPress and WooCommerce

Common issues

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readme.md

XRechnung for PHP: InvoiceXML API Examples

Get your API key

Requirements

Files in this folder

Create an XRechnung invoice in PHP

Validate an XRechnung file in PHP

Extract XRechnung data as JSON in PHP

(Experimental) Convert a plain PDF to XRechnung with AI

Render XRechnung as a readable PDF in PHP

Framework integration

Laravel

Symfony

WordPress and WooCommerce

Common issues

Resources