PHP Integration Guide

Prerequisites

PHP 7.4 or higher
cURL extension enabled
Card2Crypto account with API key

Quick Start

1. Set Up Environment Variables

Create a .env file in your project root:

# .env
CARD2CRYPTO_API_KEY=c2c_live_your_api_key_here
CARD2CRYPTO_WEBHOOK_SECRET=your_webhook_secret_here

Add to .gitignore:

.env

2. Load Environment Variables

<?php
// config.php

// Load .env file
if (file_exists(__DIR__ . '/.env')) {
    $lines = file(__DIR__ . '/.env', FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
    foreach ($lines as $line) {
        if (strpos($line, '=') !== false && strpos($line, '#') !== 0) {
            list($name, $value) = explode('=', $line, 2);
            putenv(trim($name) . '=' . trim($value));
        }
    }
}

define('CARD2CRYPTO_API_KEY', getenv('CARD2CRYPTO_API_KEY'));
define('CARD2CRYPTO_WEBHOOK_SECRET', getenv('CARD2CRYPTO_WEBHOOK_SECRET'));
define('CARD2CRYPTO_API_URL', 'https://card2crypto.cc/api/v1');

3. Create Card2Crypto Class

<?php
// lib/Card2Crypto.php

class Card2Crypto {
    private $apiKey;
    private $baseUrl = 'https://card2crypto.cc/api/v1';

    public function __construct($apiKey) {
        $this->apiKey = $apiKey;
    }

    public function createPayment($data) {
        $endpoint = $this->baseUrl . '/payments';

        $ch = curl_init($endpoint);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_POST, true);
        curl_setopt($ch, CURLOPT_HTTPHEADER, [
            'Authorization: Bearer ' . $this->apiKey,
            'Content-Type: application/json'
        ]);
        curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($data));

        $response = curl_exec($ch);
        $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);

        if (curl_errno($ch)) {
            throw new Exception('cURL error: ' . curl_error($ch));
        }

        curl_close($ch);

        $result = json_decode($response, true);

        if ($httpCode !== 200 || !$result['success']) {
            throw new Exception($result['error'] ?? 'Payment creation failed');
        }

        return $result['data'];
    }

    public function getPayment($paymentId) {
        $endpoint = $this->baseUrl . '/payments/' . $paymentId;

        $ch = curl_init($endpoint);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_HTTPHEADER, [
            'Authorization: Bearer ' . $this->apiKey
        ]);

        $response = curl_exec($ch);
        $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);

        if (curl_errno($ch)) {
            throw new Exception('cURL error: ' . curl_error($ch));
        }

        curl_close($ch);

        $result = json_decode($response, true);

        if ($httpCode !== 200 || !$result['success']) {
            throw new Exception($result['error'] ?? 'Payment retrieval failed');
        }

        return $result['data'];
    }

    public function verifyWebhookSignature($payload, $signature, $secret) {
        $expectedSignature = hash_hmac('sha256', json_encode($payload), $secret);
        return hash_equals($expectedSignature, $signature);
    }
}

Creating Payments

Basic Payment Creation

<?php
// create-payment.php

require_once 'config.php';
require_once 'lib/Card2Crypto.php';

$c2c = new Card2Crypto(CARD2CRYPTO_API_KEY);

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    try {
        $payment = $c2c->createPayment([
            'amount' => (int)$_POST['amount'], // Amount in cents
            'currency' => 'usd',
            'return_url' => 'https://yoursite.com/payment-complete.php',
            'customer_email' => $_POST['email'] ?? null,
            'customer_name' => $_POST['name'] ?? null,
            'metadata' => [
                'order_id' => $_POST['order_id'] ?? null
            ]
        ]);

        // Redirect to checkout
        header('Location: ' . $payment['checkout_url']);
        exit;

    } catch (Exception $e) {
        echo 'Error: ' . htmlspecialchars($e->getMessage());
    }
}
?>

<!DOCTYPE html>
<html>
<head>
    <title>Create Payment</title>
</head>
<body>
    <h1>Create Payment</h1>
    <form method="POST">
        <label>
            Amount (in cents):
            <input type="number" name="amount" required min="50">
        </label>
        <br>
        <label>
            Email:
            <input type="email" name="email">
        </label>
        <br>
        <label>
            Name:
            <input type="text" name="name">
        </label>
        <br>
        <label>
            Order ID:
            <input type="text" name="order_id">
        </label>
        <br>
        <button type="submit">Pay Now</button>
    </form>
</body>
</html>

Payment with Database

<?php
// create-order.php

require_once 'config.php';
require_once 'lib/Card2Crypto.php';
require_once 'lib/Database.php';

$db = new PDO('mysql:host=localhost;dbname=mydb', 'username', 'password');
$c2c = new Card2Crypto(CARD2CRYPTO_API_KEY);

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    try {
        // Create order in database
        $stmt = $db->prepare('
            INSERT INTO orders (user_id, product_name, amount, status, created_at)
            VALUES (?, ?, ?, ?, NOW())
        ');
        $stmt->execute([
            $_POST['user_id'],
            $_POST['product_name'],
            $_POST['amount'],
            'pending'
        ]);

        $orderId = $db->lastInsertId();

        // Create payment
        $payment = $c2c->createPayment([
            'amount' => (int)$_POST['amount'],
            'currency' => 'usd',
            'return_url' => 'https://yoursite.com/order-complete.php?order_id=' . $orderId,
            'metadata' => [
                'order_id' => $orderId,
                'user_id' => $_POST['user_id']
            ]
        ]);

        // Update order with payment ID
        $stmt = $db->prepare('UPDATE orders SET payment_id = ? WHERE id = ?');
        $stmt->execute([$payment['id'], $orderId]);

        // Redirect to checkout
        header('Location: ' . $payment['checkout_url']);
        exit;

    } catch (Exception $e) {
        echo 'Error: ' . htmlspecialchars($e->getMessage());
    }
}

Handling Return URL

<?php
// payment-complete.php

require_once 'config.php';
require_once 'lib/Card2Crypto.php';

$c2c = new Card2Crypto(CARD2CRYPTO_API_KEY);

if (!isset($_GET['payment_id'])) {
    http_response_code(400);
    die('Missing payment ID');
}

try {
    $payment = $c2c->getPayment($_GET['payment_id']);

    ?>
    <!DOCTYPE html>
    <html>
    <head>
        <title>Payment Status</title>
    </head>
    <body>
        <h1>Payment Status</h1>

        <?php if ($payment['status'] === 'completed'): ?>
            <h2>Payment Successful!</h2>
            <p>Payment ID: <?= htmlspecialchars($payment['id']) ?></p>
            <p>Amount: $<?= number_format($payment['amount'] / 100, 2) ?></p>
            <p>Status: Completed</p>

        <?php elseif ($payment['status'] === 'pending'): ?>
            <h2>Payment Processing</h2>
            <p>Your payment is still being processed...</p>

        <?php else: ?>
            <h2>Payment Failed</h2>
            <p>Your payment could not be processed. Please try again.</p>

        <?php endif; ?>
    </body>
    </html>
    <?php

} catch (Exception $e) {
    http_response_code(500);
    echo 'Error: ' . htmlspecialchars($e->getMessage());
}

Webhook Integration

Basic Webhook Handler

<?php
// webhook.php

require_once 'config.php';
require_once 'lib/Card2Crypto.php';

$c2c = new Card2Crypto(CARD2CRYPTO_API_KEY);

// Get raw POST body
$payload = json_decode(file_get_contents('php://input'), true);
$signature = $_SERVER['HTTP_X_CARD2CRYPTO_SIGNATURE'] ?? '';

// Verify signature
if (!$c2c->verifyWebhookSignature($payload, $signature, CARD2CRYPTO_WEBHOOK_SECRET)) {
    http_response_code(401);
    die('Invalid signature');
}

// Return 200 OK immediately
http_response_code(200);
echo 'OK';

// Log webhook
error_log('Webhook received: ' . $payload['event']);

// Process webhook based on event type
switch ($payload['event']) {
    case 'payment.completed':
        handlePaymentCompleted($payload['payment']);
        break;

    case 'payment.failed':
        handlePaymentFailed($payload['payment']);
        break;

    case 'payment.refunded':
        handlePaymentRefunded($payload['payment']);
        break;

    default:
        error_log('Unknown event type: ' . $payload['event']);
}

function handlePaymentCompleted($payment) {
    $orderId = $payment['metadata']['order_id'] ?? null;

    if (!$orderId) {
        error_log('No order ID in payment metadata');
        return;
    }

    try {
        $db = new PDO('mysql:host=localhost;dbname=mydb', 'username', 'password');

        // Update order status
        $stmt = $db->prepare('UPDATE orders SET status = ? WHERE id = ?');
        $stmt->execute(['paid', $orderId]);

        error_log("Order $orderId marked as paid");

        // Grant access to product
        // grantAccess($payment['customer_email']);

        // Send confirmation email
        // sendEmail($payment['customer_email'], 'Payment confirmed!');

    } catch (Exception $e) {
        error_log('Error processing payment: ' . $e->getMessage());
    }
}

function handlePaymentFailed($payment) {
    $orderId = $payment['metadata']['order_id'] ?? null;

    if ($orderId) {
        try {
            $db = new PDO('mysql:host=localhost;dbname=mydb', 'username', 'password');
            $stmt = $db->prepare('UPDATE orders SET status = ? WHERE id = ?');
            $stmt->execute(['payment_failed', $orderId]);

            error_log("Order $orderId marked as failed");
        } catch (Exception $e) {
            error_log('Error: ' . $e->getMessage());
        }
    }
}

function handlePaymentRefunded($payment) {
    $orderId = $payment['metadata']['order_id'] ?? null;

    if ($orderId) {
        try {
            $db = new PDO('mysql:host=localhost;dbname=mydb', 'username', 'password');
            $stmt = $db->prepare('UPDATE orders SET status = ? WHERE id = ?');
            $stmt->execute(['refunded', $orderId]);

            // Revoke access
            // revokeAccess($payment['customer_email']);

            error_log("Order $orderId refunded");
        } catch (Exception $e) {
            error_log('Error: ' . $e->getMessage());
        }
    }
}

Complete Example with Database

<?php
// Database schema (MySQL)
/*
CREATE TABLE orders (
    id INT PRIMARY KEY AUTO_INCREMENT,
    user_id INT NOT NULL,
    product_name VARCHAR(255) NOT NULL,
    amount INT NOT NULL,
    status VARCHAR(50) DEFAULT 'pending',
    payment_id VARCHAR(255) UNIQUE,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
    INDEX(user_id),
    INDEX(payment_id)
);
*/

// lib/Database.php
class Database {
    private $pdo;

    public function __construct() {
        $this->pdo = new PDO(
            'mysql:host=localhost;dbname=mydb',
            getenv('DB_USERNAME'),
            getenv('DB_PASSWORD'),
            [PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION]
        );
    }

    public function createOrder($userId, $productName, $amount) {
        $stmt = $this->pdo->prepare('
            INSERT INTO orders (user_id, product_name, amount, status)
            VALUES (?, ?, ?, ?)
        ');
        $stmt->execute([$userId, $productName, $amount, 'pending']);
        return $this->pdo->lastInsertId();
    }

    public function getOrder($id) {
        $stmt = $this->pdo->prepare('SELECT * FROM orders WHERE id = ?');
        $stmt->execute([$id]);
        return $stmt->fetch(PDO::FETCH_ASSOC);
    }

    public function updateOrderPaymentId($orderId, $paymentId) {
        $stmt = $this->pdo->prepare('UPDATE orders SET payment_id = ? WHERE id = ?');
        $stmt->execute([$paymentId, $orderId]);
    }

    public function updateOrderStatus($orderId, $status) {
        $stmt = $this->pdo->prepare('UPDATE orders SET status = ? WHERE id = ?');
        $stmt->execute([$status, $orderId]);
    }
}

// checkout.php
require_once 'config.php';
require_once 'lib/Card2Crypto.php';
require_once 'lib/Database.php';

$c2c = new Card2Crypto(CARD2CRYPTO_API_KEY);
$db = new Database();

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    try {
        // Create order
        $orderId = $db->createOrder(
            $_POST['user_id'],
            $_POST['product_name'],
            $_POST['amount']
        );

        // Create payment
        $payment = $c2c->createPayment([
            'amount' => (int)$_POST['amount'],
            'currency' => 'usd',
            'return_url' => 'https://yoursite.com/complete.php?order_id=' . $orderId,
            'metadata' => [
                'order_id' => $orderId,
                'user_id' => $_POST['user_id']
            ]
        ]);

        // Update order with payment ID
        $db->updateOrderPaymentId($orderId, $payment['id']);

        // Redirect to checkout
        header('Location: ' . $payment['checkout_url']);
        exit;

    } catch (Exception $e) {
        http_response_code(500);
        echo 'Error: ' . htmlspecialchars($e->getMessage());
    }
}

Error Handling

<?php
// lib/Card2CryptoException.php

class Card2CryptoException extends Exception {
    private $statusCode;
    private $response;

    public function __construct($message, $statusCode = 500, $response = null) {
        parent::__construct($message);
        $this->statusCode = $statusCode;
        $this->response = $response;
    }

    public function getStatusCode() {
        return $this->statusCode;
    }

    public function getResponse() {
        return $this->response;
    }
}

// Updated Card2Crypto class with better error handling
class Card2Crypto {
    // ... existing code ...

    public function createPayment($data) {
        $endpoint = $this->baseUrl . '/payments';

        $ch = curl_init($endpoint);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_POST, true);
        curl_setopt($ch, CURLOPT_HTTPHEADER, [
            'Authorization: Bearer ' . $this->apiKey,
            'Content-Type: application/json'
        ]);
        curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($data));

        $response = curl_exec($ch);
        $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);

        if (curl_errno($ch)) {
            throw new Card2CryptoException('Network error: ' . curl_error($ch));
        }

        curl_close($ch);

        $result = json_decode($response, true);

        if ($httpCode !== 200) {
            throw new Card2CryptoException(
                $result['error'] ?? 'Payment creation failed',
                $httpCode,
                $result
            );
        }

        if (!$result['success']) {
            throw new Card2CryptoException($result['error'] ?? 'Unknown error', $httpCode);
        }

        return $result['data'];
    }
}

// Usage with error handling
try {
    $payment = $c2c->createPayment([
        'amount' => 10000,
        'currency' => 'usd',
        'return_url' => 'https://yoursite.com/success'
    ]);

    header('Location: ' . $payment['checkout_url']);
    exit;

} catch (Card2CryptoException $e) {
    error_log('Card2Crypto error (' . $e->getStatusCode() . '): ' . $e->getMessage());
    http_response_code($e->getStatusCode());
    echo 'Payment error: ' . htmlspecialchars($e->getMessage());

} catch (Exception $e) {
    error_log('Unexpected error: ' . $e->getMessage());
    http_response_code(500);
    echo 'An unexpected error occurred';
}

Testing

Local Testing

# Install PHP built-in server
php -S localhost:8000

# Use ngrok to expose locally
ngrok http 8000

# Use ngrok URL in webhook settings
# https://abc123.ngrok.io/webhook.php

Best Practices

Never expose API keys in frontend code
Always verify webhook signatures
Use prepared statements to prevent SQL injection
Validate and sanitize all user input
Log all payment-related events
Handle errors gracefully
Use HTTPS in production
Keep dependencies updated
Test with real payments before going live
Implement proper error logging

Security Checklist

Store API keys in environment variables
Use HTTPS for all payment pages
Verify webhook signatures
Sanitize all user input
Use prepared statements for database queries
Enable PHP error logging
Set appropriate file permissions
Keep PHP version updated
Use secure session handling

Next Steps

API Reference

Complete API documentation

Webhook Security

Learn about webhook verification

Node.js Guide

Integration guide for Node.js

Testing Guide

How to test your integration

Get Started

Core Concepts

Integration Guides

Webhooks

Resources

PHP Integration Guide

Prerequisites

Quick Start

1. Set Up Environment Variables

2. Load Environment Variables

3. Create Card2Crypto Class

Creating Payments

Basic Payment Creation

Payment with Database

Handling Return URL

Webhook Integration

Basic Webhook Handler

Complete Example with Database

Error Handling

Testing

Local Testing

Best Practices

Security Checklist

Next Steps

API Reference

Webhook Security

Node.js Guide

Testing Guide

​Prerequisites

​Quick Start

​1. Set Up Environment Variables

​2. Load Environment Variables

​3. Create Card2Crypto Class

​Creating Payments

​Basic Payment Creation

​Payment with Database

​Handling Return URL

​Webhook Integration

​Basic Webhook Handler

​Complete Example with Database

​Error Handling

​Testing

​Local Testing

​Best Practices

​Security Checklist

​Next Steps

API Reference

Webhook Security

Node.js Guide

Testing Guide

Prerequisites

Quick Start

1. Set Up Environment Variables

2. Load Environment Variables

3. Create Card2Crypto Class

Creating Payments

Basic Payment Creation

Payment with Database

Handling Return URL

Webhook Integration

Basic Webhook Handler

Complete Example with Database

Error Handling

Testing

Local Testing

Best Practices

Security Checklist

Next Steps