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How to Integrate PhonePe Payment Gateway in PHP

By Aakash : Integrating PhonePe with your PHP-based website allows you to offer a seamless payment experience. This guide walks you through creating a payment order, redirecting the user to PhonePe, and handling the callback to confirm the transaction.

🔄 How to Integrate PhonePe Payment Gateway in PHP

Integrating PhonePe with your PHP-based website allows you to offer a seamless payment experience. This guide walks you through creating a payment order, redirecting the user to PhonePe, and handling the callback to confirm the transaction.

🛒 Step 1: Capture the Order and Redirect to Confirmation

After the customer places an order, show a confirmation page summarizing their order. Include a Submit & Pay button that, when clicked, redirects the user to checksum.php.

🧾 Step 2: Construct the Payment Payload in checksum.php

Fetch the order details and generate a unique transaction ID. Then, create the payload:

$amount = $orderAmount * 100; // Convert to paise
$eventPayload = [
    'merchantId' => 'YOUR_MERCHANT_ID',
    'merchantTransactionId' => uniqid('TXN'),
    'merchantUserId' => 'USER123',
    'amount' => $amount,
    'redirectUrl' => 'https://yourdomain.com/callback.php',
    'redirectMode' => 'POST',
    'callbackUrl' => 'https://yourdomain.com/callback.php',
    'mobileNumber' => '9999999999',
    'paymentInstrument' => [
        'type' => 'PAY_PAGE',
    ],
];
$encodedPayload = base64_encode(json_encode($eventPayload));

🔐 Step 3: Generate X-VERIFY Header

$saltKey = 'YOUR_SALT_KEY';
$saltIndex = 1;
$stringToHash = $encodedPayload . '/pg/v1/pay' . $saltKey;
$checksum = hash('sha256', $stringToHash);
$finalXHeader = $checksum . '###' . $saltIndex;

📡 Step 4: Send the Payment Request to PhonePe API

$headers = [
    'Content-Type: application/json',
    'X-VERIFY: ' . $finalXHeader,
];
$phonePeUrl = 'https://api.phonepe.com/apis/hermes/pg/v1/pay'; // Production endpoint
$data = ['request' => $encodedPayload];

$options = [
    'http' => [
        'method' => 'POST',
        'content' => json_encode($data),
        'header' => implode("rn", $headers),
    ],
];

$context = stream_context_create($options);
$response = file_get_contents($phonePeUrl, false, $context);
$result = json_decode($response, true);
$redirectUrl = $result['data']['instrumentResponse']['redirectInfo']['url'];

💳 Step 5: Redirect to PhonePe Checkout

Embed the checkout script and initiate the transaction:

<script src="https://mercury.phonepe.com/web/bundle/checkout.js"></script>
<script>
    var tokenUrl = '<?php echo $redirectUrl; ?>';
    window.PhonePeCheckout.transact({ tokenUrl });
</script>

🔔 Step 6: Handle the Payment Callback

After payment completion, PhonePe will send a POST request to your callback.php with transaction details.

1️⃣ Receive the Callback Data

$transactionId = $_POST['transactionId'];

2️⃣ Construct the X-VERIFY Header for Payment Status Check

$gateway = (object) [
    'token' => 'YOUR_MERCHANT_ID',
    'secret_key' => 'YOUR_SALT_KEY',
];

$orderId = $transactionId;
$checksumString = '/pg/v1/status/' . $gateway->token . '/' . $orderId . $gateway->secret_key;
$encodeIn256 = hash('sha256', $checksumString) . '###1';

3️⃣ Call the PhonePe Status API

$headers = [
    'Content-Type: application/json',
    'X-MERCHANT-ID: ' . $gateway->token,
    'X-VERIFY: ' . $encodeIn256,
    'Accept: application/json',
];

$phonePeStatusUrl = 'https://api.phonepe.com/apis/hermes/pg/v1/status/' . $gateway->token . '/' . $orderId;

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $phonePeStatusUrl);
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$response = curl_exec($ch);
curl_close($ch);

$apiResponse = json_decode($response);

4️⃣ Process the Payment Status

Store the callback and status response for logging or debugging:

$serializedPostData = serialize($_POST);
$serializedApiResponse = serialize($apiResponse);

Then, check the payment status:

if ($apiResponse->code == "PAYMENT_SUCCESS") {
    // ✅ Payment successful: Update order status, notify user, fulfill order.
} else {
    // ❌ Payment failed or pending: Handle accordingly.
}