PHP HTML to PDF API guide
Use PHP and cURL to generate PDFs from Laravel, Symfony, WordPress, or plain PHP backends.
Overview
Post JSON to the API, validate the HTTP response, and save or stream the generated PDF from PHP.
The API accepts a JSON request body. Send either a public URL or inline HTML in the required html parameter. For normal synchronous conversions, the response body is the generated PDF and should be saved as binary data.
Requirements
- PHP 8.1 or newer
- The PHP cURL extension
- An html2pdf.app API key stored outside public code
Quick start
Replace <your-api-key> or the environment variable with your html2pdf.app API key, then run the example from a trusted backend environment.
This example sends a URL to the API and writes the successful binary response to document.pdf.
<?php
$payload = [
'html' => 'https://www.example.com',
];
$ch = curl_init('https://api.html2pdf.app/v1/generate');
curl_setopt_array($ch, [
CURLOPT_POST => true,
CURLOPT_RETURNTRANSFER => true,
CURLOPT_POSTFIELDS => json_encode($payload),
CURLOPT_HTTPHEADER => [
'Content-Type: application/json',
'X-API-Key: ' . getenv('HTML2PDF_API_KEY'),
],
]);
$pdf = curl_exec($ch);
$statusCode = curl_getinfo($ch, CURLINFO_RESPONSE_CODE);
$error = curl_error($ch);
curl_close($ch);
if ($pdf === false || $statusCode < 200 || $statusCode >= 300) {
throw new RuntimeException($error ?: 'PDF generation failed');
}
file_put_contents(__DIR__ . '/document.pdf', $pdf);PHP examples
These examples cover the next common production flows: generating from inline HTML with options and queuing a callback job.
1. Stream the PDF from a controller
Return the generated PDF to the browser from server-side PHP without exposing your API key.
<?php
$payload = [
'html' => '<h1>Receipt</h1><p>Thank you for your order.</p>',
'filename' => 'receipt.pdf',
'format' => 'A4',
'marginTop' => 32,
'marginBottom' => 32,
];
$ch = curl_init('https://api.html2pdf.app/v1/generate');
curl_setopt_array($ch, [
CURLOPT_POST => true,
CURLOPT_RETURNTRANSFER => true,
CURLOPT_POSTFIELDS => json_encode($payload),
CURLOPT_HTTPHEADER => [
'Content-Type: application/json',
'X-API-Key: ' . getenv('HTML2PDF_API_KEY'),
],
]);
$pdf = curl_exec($ch);
$statusCode = curl_getinfo($ch, CURLINFO_RESPONSE_CODE);
curl_close($ch);
if ($statusCode < 200 || $statusCode >= 300) {
http_response_code(502);
echo 'Unable to generate PDF';
exit;
}
header('Content-Type: application/pdf');
header('Content-Disposition: inline; filename="receipt.pdf"');
echo $pdf;2. Start an asynchronous conversion
Use callBackUrl when PHP should submit the job and let another endpoint receive the PDF later.
<?php
$payload = [
'html' => 'https://www.example.com/report',
'callBackUrl' => 'https://your-app.com/webhooks/html2pdf',
'state' => 'report-1042',
];
$ch = curl_init('https://api.html2pdf.app/v1/generate');
curl_setopt_array($ch, [
CURLOPT_POST => true,
CURLOPT_RETURNTRANSFER => true,
CURLOPT_POSTFIELDS => json_encode($payload),
CURLOPT_HTTPHEADER => [
'Content-Type: application/json',
'X-API-Key: ' . getenv('HTML2PDF_API_KEY'),
],
]);
$response = curl_exec($ch);
$statusCode = curl_getinfo($ch, CURLINFO_RESPONSE_CODE);
curl_close($ch);
if ($statusCode < 200 || $statusCode >= 300) {
throw new RuntimeException('Unable to queue PDF conversion');
}Request options
Most integrations start with html and then add options as the document design becomes more specific.
htmlis required and accepts a public URL or raw HTML.format,landscape,width, andheightcontrol page size.marginTop,marginRight,marginBottom, andmarginLeftcontrol whitespace around the rendered page.mediaselectsscreenorprintCSS rendering.callBackUrlswitches the request to asynchronous generation and sends the completed PDF to your webhook.
See the full API parameter reference for every supported field.
Troubleshooting
- Use getenv or your framework secrets manager for the API key.
- Check CURLINFO_RESPONSE_CODE before streaming the response as a PDF.
- Do not call the API directly from browser JavaScript rendered by PHP.
If the generated document is blank or missing styles, first confirm that the source URL is public and that required CSS, fonts, and images are reachable by the rendering service.