The KIX extension is given to files whose content is code written in a scripting programming language called KiXtart. The KIX file contains a script that can be used with Microsoft Windows and Windows Server. Scripts are used to automate the sequence of certain activities in the system and to supervise certain events, for example logging.

The KiXtart language has a built-in mechanism to facilitate the creation of scripts. It supports, among others, the ADSI programming interface or the ActiveX Data Objects standard. The author of KiXtart is Ruud van Velsen.