How to Create a Custom WHMCS Payment Gateway

Building a Custom Payment Gateway

Payment gateways are essential for any WHMCS installation. Learn how to create one from scratch.

Prerequisites

Module Structure

Create your gateway in /modules/gateways/:

 ['Type' => 'System', 'Value' => 'Your Gateway'],
        'apiKey' => ['FriendlyName' => 'API Key', 'Type' => 'text', 'Size' => '50'],
        'secretKey' => ['FriendlyName' => 'Secret Key', 'Type' => 'password', 'Size' => '50'],
        'testMode' => ['FriendlyName' => 'Test Mode', 'Type' => 'yesno']
    ];
}

Handling Payments

Implement the _link function for redirect-based payments or _capture for direct capture.

Webhook Handling

Create a callback file to handle payment notifications from the processor.

Security Considerations