.FPI files are script or programs created with FPS Creator, a 3D first-person shooter (FPS) game development program used to simplify game programming for users with limited programming experience. .FPI files are generally used to develop the artificial intelligence (AI) for the characters within the game. .FPI files are saved in a plain text format that can be viewed and edited with a text editor such as Windows Notepad. .FPI files can then be compiled into an executable program using the FPS Creator application.