Version 5.x System Requirements
From WHMCS Documentation
WHMCS requires the following in order to run:
- PHP Version 4.2.x or later
- MySQL Version 4.1.x or later
- Curl Support (with SSL support)
- GD Image Library
- Ioncube Loaders Support
WHMCS does not need to be tied to a server for automatic account provisioning in order to function. You can use the system as a standalone billing & support center without any issues.