The Buddy Development Kit (BDK) is a COM/ActiveX library that allows you to communicate with Buddy devices. Using BDK you can configure Buddy devices, receive event notifications like button clicks, act on device parts like turn on a led setting its color to green, and even configure the event/action table inside the device in order to fully configure the device to act in a custom way.
You can use BDK from your preferred programming language, like C, C++, C#, Delphi and any other language that can create and access COM/ActiveX objects. BDK is accessible even from VBScript files or Microsoft Word/Excel macros. The BDK communicates with Buddy devices through the USB and performs all low-level actions on them. As for the application side, BDK provides high-level objects, interfaces, methods and properties that make it easy to use Buddy devices programatically. This documentation lists all those objects and interfaces and their available methods and properties.