# Modules

## Introduction

A module is a collection of functions that provide additional functionality to the WHMCS platform, most commonly used to integrate with third party services and APIs.

#### Choose a module type to begin...

div
div
a
i
h3
Provisioning Modules
p
For modules that enable provisioning and management of products and services via API.
div
a
i
h3
Addon Modules
p
Create a module that provides additional functionality within WHMCS.
div
a
i
h3
Registrar Modules
p
Connect with domain registrars to allow for availability checking, domain registration and management.
div
a
i
h3
Gateway Modules
p
Integrate with payment gateway providers to collect and process payments.
div
a
i
h3
Mail Provider Modules
p
Add custom mail providers to WHMCS.
div
a
i
h3
Notification Providers
p
Integrate additional notification services for use with the Notifications system.