Judge0 (pronounced like "judge zero") is a robust, scalable, and open-source online code execution system. You can use it to build a wide range of applications that need online code execution features. Some examples include competitive programming platforms, e-learning platforms, candidate assessment and recruitment platforms, online code editors, online IDEs, and many more.

In our research paper Robust and Scalable Online Code Execution System, we present Judge0's modern modular architecture that can be easily deployed and scaled. We study its design, comment on the various challenges in building such systems, and compare it with other available online code execution systems and online judge systems.

To see Judge0 in action, try Judge0 IDE - our free and open-source online code editor.