PyWebGL is an object-oriented Python 3 package for composition, simulation and debugging of WebGL 2.0 Programs. It is based on the Khronos Group's WebGL 2.0 reference. It is specifically intended to aid the high-level algorithmic design and analysis of WebGL programs. Note that PyWebGL is not intended as a substitute for existing WebGL debugging tools: exact or near-exact simulation of WebGL code is not a goal of this project.