ProxCP Admin - Manage API
From ProxCP Documentation
This page allows Admin users to create and remove ProxCP API credentials. This API is used for the WHMCS and Blesta billing modules only. The ProxCP API is not usable outside of those billing modules.
API authentication is done using a randomly generated ID and key. This ID/key combination is also restricted to a single IP address - this IP is usually the IP address of your WHMCS or Blesta installation.