Harvie’s CNC Simulator is a popular in-browser g-code simulator, with 47 stars and 138 forks on GitHub. Originally part of the JSCut CAM package, it was modified for offline use by Tomas Mudrunka in 2024. The simulator allows users to load g-code from a file, pass settings and g-code via URL, and supports arcs. It works offline without needing a webserver. Some features are still in development, such as 3D view zooming and tool library support. The simulator is a useful tool for those working with CNC machines. Check it out at harvie.github.io/cnc-simulator.
https://github.com/Harvie/cnc-simulator