Judge0 - Code Execution Made Simple for Every Business | WarmIndex

Judge0 is a robust, scalable, open-source online code execution system that enables secure, sandboxed execution of code in 90+ programming languages via a simple API, perfect for developers, educators, AI agents, and businesses building coding platforms.

🚀 Overview

Judge0 is an open-source platform that provides a secure and scalable way to execute untrusted code online. It powers applications like competitive programming judges, online IDEs, e-learning platforms, coding assessment tools for recruitment, and AI code runners by offering sandboxed compilation and execution in over 90 programming languages.

The problem it solves is safely running user-submitted code without risking the host system, using Isolate for sandboxing and Docker for isolation. It's built for developers integrating code execution into their apps, educators teaching programming, students practicing, companies hiring via coding tests, and AI systems needing to verify generated code.

Created in 2016 by Herman Zvonimir Došilović, Judge0 was built to make online code execution simple, fast, and accessible for everyone—from hobbyists to enterprises—with easy self-hosting or cloud options.

✨ Key Features

Secure sandboxed execution with Isolate, supporting 90+ languages, multi-file programs, custom compiler flags, stdin, time/memory limits, and detailed results including stdout/stderr.
Rich HTTP JSON API with synchronous/async modes, webhooks for callbacks, and official Python SDK for easy integration.
Scalable architecture deployable via Docker Compose for self-hosting; cloud version available on RapidAPI.
Free online IDE (https://ide.judge0.com) with Monaco Editor, syntax highlighting, themes, and embeddable widget; mobile IDE coming soon.
Optional: Experimental features like AI agent support and extra language packs (Judge0 Extra CE).

🛠 Tech Stack

Frontend: JavaScript, Monaco Editor (for IDE)
Backend: Ruby on Rails, Isolate (sandboxing)
Database: Redis (caching/queues)
Auth: API keys (cloud), custom for self-host
Hosting: Docker, self-hosted or RapidAPI cloud

👥 Who Is This For?

This project is useful for:

Developers who want to add online code execution to apps like judges, IDEs, or AI tools
Teams looking for scalable code assessment in hiring and education platforms
Indie makers building competitive programming sites or e-learning tools

📸 Screenshots / Demo

Live demo: https://ide.judge0.com
GitHub: https://github.com/judge0/judge0

🔥 Project Status

🟢 Actively building

Last updated: 2026-03-24

❓ FAQ

Is this project free?

Freemium / Open Source — Self-host for free (GPL-3.0); cloud hosted on RapidAPI with free tier and paid plans starting at €27/month for Pro (2000 submissions/day + €0.001/extra).

Is the source code available?

Yes — https://github.com/judge0/judge0 (core engine), https://github.com/judge0/ide (online IDE)

Can I contribute?

Yes — Check CONTRIBUTING.md, open issues, submit PRs on GitHub, join Discord at https://discord.judge0.com, or provide feedback via email.

📬 Contact & Links

Built with ❤️ and kept warm on WarmIndex.

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