WHMCS is the all-in-one client management system for Reseller Hosting. It is a WHM plugin that gives you billing and support capabilities so you have all the tools to run their hosting business.
With WHMCS you can set up billing, hosting packages, payment gateways, server provisioning APIs, domain registration and fraud protection services.
There are many customizable options within WHMCS. To learn more about WHMCS, see the WHMCS website.