How to Integrate FamPay Gateway in PHP (Step-by-Step 2026 Developer Tutorial)

If you are developing a PHP application, an e-commerce storefront, or a membership portal in India and want to accept automated payments via FamPay (FamApp by Trio), you quickly discover that there is no official merchant API for individual creators. Aggregators like Razorpay require corporate entities and GST certificates, while manual UPI transfers leave you vulnerable to fake screenshot scams.

That is where FamGateway steps in. In this step-by-step 2026 guide, you will learn how to integrate automated FamPay UPI payments into any PHP website using either the official FamGateway PHP SDK or standard native PHP cURL requests, complete with cryptographic HMAC-SHA256 webhook verification.

Step 1: Obtain Your Free API Credentials

To begin, create your free account on FamGateway Registration:

1. Navigate to Dashboard → Gmail Settings and enter your FamPay-linked Gmail address.
2. Generate a 16-character Google App Password and save it.
3. Enter your FamPay UPI ID (e.g., yourname@fam).
4. Go to the API Keys tab to copy your live private api_key.

Step 2: Integration Method A — Official FamGateway PHP SDK

The simplest, cleanest way to integrate is using our official open-source PHP SDK (GitHub Repository).

You can install the SDK via Composer:

composer require aryanispe/famgateway-php-sdk

Or simply download FamGateway.php and include it directly in your project:

<?php
require_once 'FamGateway.php';

// Initialize SDK with your private API Key
$fg = new FamGateway("YOUR_FAMGATEWAY_API_KEY");

$amount = 499.00;
$redirectUrl = "https://yourwebsite.com/payment-success.php";
$customWebhook = "https://yourwebsite.com/webhook.php";

// Creates order session and immediately redirects buyer to Hosted Checkout
$fg->createPayment($amount, $redirectUrl, $customWebhook);
?>

Step 3: Integration Method B — Native Pure PHP cURL (Zero Dependencies)

If you prefer zero external dependencies, you can call our canonical REST API directly using standard PHP cURL functions:

<?php
$apiKey = 'YOUR_FAMGATEWAY_API_KEY';
$payload = json_encode([
    'amount' => 499.00,
    'customer_name' => 'Karan Sharma',
    'redirect_url' => 'https://yourwebsite.com/payment-success.php',
    'webhook_url'  => 'https://yourwebsite.com/webhook.php'
]);

$ch = curl_init('https://famgateway.in/api/create-order');
curl_setopt_array($ch, [
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_POST => true,
    CURLOPT_POSTFIELDS => $payload,
    CURLOPT_HTTPHEADER => [
        'Content-Type: application/json',
        'X-Api-Key: ' . $apiKey
    ],
    CURLOPT_TIMEOUT => 15
]);

$response = curl_exec($ch);
if (curl_errno($ch)) {
    die("cURL Error: " . curl_error($ch));
}
curl_close($ch);

$data = json_decode($response, true);

if (($data['status'] ?? '') === 'success') {
    $checkoutUrl = $data['data']['checkout_url'];
    $qrImageUrl  = $data['data']['qr_url'];
    $upiIntent   = $data['data']['upi_intent'];

    // Option 1: Redirect buyer directly to FamGateway's hosted mobile checkout
    header("Location: " . $checkoutUrl);
    exit;

    // Option 2: Embed $qrImageUrl directly into your custom checkout page
} else {
    die("API Error: " . htmlspecialchars($data['message'] ?? 'Unknown failure'));
}
?>

Step 4: Handling Authenticated Webhooks (Instant Delivery)

When the customer pays in FamApp or any UPI app, FamGateway's stateless daemon verifies the payment in 3 to 5 seconds and dispatches an authenticated HTTP POST notification to your webhook URL.

Create a file named webhook.php on your server with cryptographic HMAC-SHA256 signature verification:

<?php
// webhook.php — Production Webhook Receiver
$apiKey = 'YOUR_FAMGATEWAY_API_KEY';

$rawBody = file_get_contents('php://input');
$signature = $_SERVER['HTTP_X_FAMGATEWAY_SIGNATURE'] ?? '';

// 1. Validate signature using constant-time comparison
$expectedSignature = hash_hmac('sha256', $rawBody, $apiKey);
if (!hash_equals($expectedSignature, $signature)) {
    http_response_code(401);
    die(json_encode(['error' => 'Invalid HMAC signature']));
}

$payload = json_decode($rawBody, true);

// 2. Process verified payment event
if (($payload['status'] ?? '') === 'success') {
    $orderId    = $payload['order_id'];
    $amount     = (float)$payload['amount'];
    $utr        = $payload['utr'];
    $senderName = $payload['sender_name'] ?? 'Buyer';

    // Atomically unlock product or update database
    // fulfillOrder($orderId, $utr, $amount);

    http_response_code(200);
    echo json_encode(['status' => 'acknowledged']);
    exit;
}

http_response_code(400);
echo json_encode(['status' => 'ignored']);
?>

Step 5: Polling Payment Status from Frontend JavaScript

If you are displaying the QR code directly on your custom page, you can poll our fast status endpoint from client-side JavaScript every 3 to 5 seconds:

// Client-side Polling Example
const checkPaymentStatus = async (orderId) => {
    try {
        const response = await fetch(`https://famgateway.in/api/checkout-status.php?order_id=${orderId}`);
        const result = await response.json();

        if (result.status === 'success') {
            window.location.href = '/order-complete.php?utr=' + result.utr;
        }
    } catch (err) {
        console.error('Polling error:', err);
    }
};

// Poll every 3 seconds
setInterval(() => checkPaymentStatus('fg_ORD_12345'), 3000);

Why PHP Developers Choose FamGateway

Frequently Asked Questions (FAQ)

Conclusion

Integrating FamPay into your PHP project takes less than 10 minutes and requires zero corporate bureaucracy. By leveraging FamGateway's stateless API and official PHP SDK, you deliver an automated, instant payment experience for your users with zero commission cuts.

Get Your Free FamPay API Key →

Back to Homepage →