An addon module allows you to add additional functionality to WHMCS. It can provide both client and admin facing user interfaces, as well as utilise hook functionality within WHMCS.

This sample file demonstrates how an addon module for WHMCS should be structured and exercises all supported functionality.

For more information, please refer to the online documentation at https://developers.whmcs.com/addon-modules/

The recommended structure of an addon module is as follows.

 addonmodule/
  |- lang/
  |- lib/
  |- templates/
  |  addonmodule.php
  |  hooks.php
  |  logo.png

For the latest WHMCS minimum system requirements, please refer to http://docs.whmcs.com/System_Requirements

We recommend your module follows the same minimum requirements wherever possible.

We strongly encourage you to write unit tests for your work. Within this SDK we provide a sample unit test based upon the widely used PHPUnit.

• Developer Portal
• Hook Documentation
• API Documentation

WHMCS Limited