Exgen is a flexible general purpose platform for building modular applications. You can write your application as compatible binary modules that Exgen can load and run. Modules can be loaded and unloaded dynamically and run in the same thread or a new thread. A mechanism for inter-thread communication is provided. Modules can also run Lua scripts, both in a single thread or in new threads. Exgen can function as a stand-alone Lua host with all the same capabilities, allowing entire applications to be written in Lua. Modules can also function as libraries, extending the functionality of both other modules and Lua scripts.