Developer Resources

For developers, WHMCS has all the capabilities you might need to allow you to customize, integrate & extend the core system into your own website & applications.

Display Customisation

Help & information relating to the customisation of templates and language files within WHMCS.

• Template Syntax
• Client Area Templates
• Admin Area Templates
• Order Form Templates
• PDF Invoice
• Client Area Language Files
• Admin Area Language Files

Extending Functionality

Detailed developer documentation & resources for how to create modules, pages and use hooks to integrate & extend system functionality.

• Module Development Kit - guide & template for creating your own product/server provisioning modules
• Registrar Development Kit - guide & template for creating a domain registrar module
• Gateway Development Kit - guide & template for creating a payment gateway module
• SQL Helper Functions - how to use the MySQL functions built into WHMCS
• Addon Modules - addon modules allow you to create both custom admin pages and hooks for additional functionality
• Creating Pages - demonstrates how to create custom pages for the client area
• Action Hooks - hooks allow you to run your own code when various events & actions occur inside WHMCS
• AutoAuth - for automatically authenticating clients from custom code

API

The API docs provide details and code samples for interfacing with the WHMCS API from both within WHMCS itself, and outside it from custom code or third party applications.

• API Information - overview & setup info
• Internal API - details & example code for calling the WHMCS API locally from within WHMCS modules & files
• Example XML Method Code - sample PHP code for calling & interpreting the XML responses of the WHMCS API
• Example JSON Method Code - sample PHP code for calling & interpreting JSON responses from the WHMCS API
• API Functions - individual documentation for all the functions of the API