Judge0

Judge0 is an open-source online code execution system that provides secure, sandboxed code compilation and execution for humans and AI.

Judge0 is an open-source, scalable system designed to execute code in sandboxed environments. It enables the creation of applications requiring online code execution, such as AI-generated code tools, competitive programming platforms, candidate assessment portals, and online IDEs. Users can specify custom input, compiler options, command-line arguments, and set time and memory limits. It returns detailed execution results and supports webhooks for status updates. The system provides its execution engine through an API for integration into other software, or via dedicated web and mobile IDE applications.

Judge0 at a glance

Best for: Software engineer
Runs on: Web, iOS, Android, API, self-hosted
Pricing: Free plan includes 2000 submissions/day; extra submissions cost €0.001 each. Paid plans offer 5000 and 10,000 submissions/day.
Released: January 2017
Category: AI coding tool
Website: judge0.com

Key features

Support for 60+ programming languages
Sandboxed compilation and execution
API with verbose documentation
Configurable compiler options and command-line arguments
Time and memory limit enforcement
Detailed execution results
Webhook support via HTTP callbacks

Use it for

AI-generated code execution
Competitive programming platforms
E-learning and programming instruction
Candidate assessment and recruitment
Online code editors and IDEs

Companions

Tools that articles about Judge0 recommend using with it, each with its job.

Context7 — Provides up-to-date documentation for AI agents and code editors.
Ollama — Run local models at zero marginal cost, with code kept on your machine.
OpenRouter — Access over 500 models and 80 providers through one unified API.
Daytona — Runs sessions in isolated sandboxes synced to git branches.
Composio — Equips AI agents with tools, managed user auth, and sandboxes across 1,500+ apps
Oh My OpenCode Slim — Lightweight multi-agent orchestration and background tasks.

Alternatives to Judge0

OpenCode — Works with 75+ model providers, local models, and existing subscriptions
OpenSandbox — Provides isolated environments with multi-language SDKs and lifecycle management.
OneCompiler — It supports over 110 programming languages and databases with no installation.
jevgrep — Reduces coding agent costs by providing targeted, relevant repository context.
Stagewise — Maintain full sovereignty over AI models while running agents in parallel.
Strata — Runs large AI models locally on consumer gaming PCs without server reliance.
Eval Skills — Guides coding agents from first execution to validated graders and experiments.
Command Code — Repairs open model tool calls and learns developer patterns automatically.
Tencent CodeBuddy — Offers multi-model support and context-aware coding assistance across many IDEs.
OpenClaude — Connects one terminal interface to over 200 different AI models.
iii — Adds services as workers in any language without writing glue code.
TRAE — It features an autonomous coding agent that drives the entire development process.

All Judge0 alternatives