This substitute foundation is a drop-in replacement for RGSS. At the time of this writing, this includes: JRGSS replaces this underlying layer of C with a Java foundation, allowing games to be run on any platform which supports version 8 or higher of the Java Virtual Machine. Because this portion of the codebase is written specifically for Windows, it causes the entire game engine to be limited to a single platform. However, in order to provide low-level graphics and audio functionality, parts of RGSS are implemented in C code tailored to interact with the Win32 API. The majority of RGSS is implemented in Ruby, a high level programming language that can run on virtually any operating system.

It was originally created for the game Vidar. JRGSS is an open source, alternative implementation of RGSS, the game engine that underlies all games developed with RPG Maker VX Ace.