Add E-Signatures to PHP

Quick start

1. Get an API key from signb.ee (free, no credit card)
2. Set SIGNBEE_API_KEY in your environment
3. Add the code below to your app

PHP example

<?php
$data = json_decode(file_get_contents('php://input'), true);

$ch = curl_init('https://signb.ee/api/send');
curl_setopt_array($ch, [
    CURLOPT_POST => true,
    CURLOPT_POSTFIELDS => json_encode($data),
    CURLOPT_HTTPHEADER => [
        'Authorization: Bearer ' . getenv('SIGNBEE_API_KEY'),
        'Content-Type: application/json',
    ],
    CURLOPT_RETURNTRANSFER => true,
]);

$response = curl_exec($ch);
curl_close($ch);

header('Content-Type: application/json');
echo $response;

What happens

1. Your app sends markdown or a PDF URL to Signbee
2. Signbee generates a PDF (if markdown) and emails the recipient a signing link
3. Recipient signs — both parties receive the signed PDF with SHA-256 certificate

Also works with AI agents

Install the MCP server to let Claude, Cursor, or Windsurf send documents directly:

npx -y signbee-mcp

Integration details

PHP powers over 75% of websites with known server-side languages. Adding e-signatures to PHP requires just cURL — a built-in extension available in virtually all PHP installations.

No framework required: The example uses pure PHP with cURL — no framework needed. This works on shared hosting, VPS, dedicated servers, or any environment with PHP and cURL enabled. It's the most universally compatible integration.

cURL vs Guzzle: The example uses PHP's built-in cURL functions. If your project uses Composer, consider Guzzle for cleaner syntax and better error handling. Both produce identical API calls.

WordPress integration: For WordPress sites, use wp_remote_post() instead of cURL. This uses WordPress's HTTP API with built-in retry logic, proxy support, and consistent error handling across different server configurations.

Error handling: Check curl_errno() and curl_error() after curl_exec() for network errors. Parse the response JSON and check for error keys returned by the API. Handle 401 (invalid key), 400 (missing fields), and 429 (rate limited) status codes.

PHP 8+ features: On PHP 8+, use named arguments for cleaner cURL configuration and match expressions for response status handling. The Fiber class (PHP 8.1+) enables async-like patterns for concurrent API calls.

FAQs