@javaguru/server-judge0

v1.1.0

Published

4 months ago

MCP server for executing code in 70+ programming languages using Judge0 CE API

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mcp model-context-protocol judge0 code-execution code-runner sandbox programming-languages librechat ai-tools llm-tools python javascript compiler

Judge0 MCP Server

Execute code in 70+ programming languages via Model Context Protocol (MCP)

A production-ready MCP server that provides secure code execution capabilities using the Judge0 CE API. Perfect for AI agents, chatbots, and any application needing sandboxed code execution.

✨ Features

🚀 70+ Programming Languages - Python, JavaScript, Java, C++, Go, Rust, PHP, Ruby, and more
🔒 Secure Sandboxed Execution - Isolated containers with resource limits
⚡ Auto Language Detection - Automatically identifies programming language from code
📊 Performance Metrics - Execution time and memory usage tracking
🆓 FREE Tier Available - 50 executions/day via RapidAPI
🏠 Self-Hosting Support - Unlimited FREE usage with your own Judge0 instance
🛠️ 4 MCP Tools - Flexible execution options
📖 Comprehensive Documentation - Guides, examples, and troubleshooting

🚀 Quick Start

Prerequisites

Node.js 18+ installed
Judge0 API key from RapidAPI (FREE tier available)

Installation

Option 1: Using npx (Recommended)

No installation needed! Just configure your MCP client to use:

npx -y @javaguru/server-judge0

Option 2: Local Installation

# Clone the repository
git clone https://github.com/YOUR_USERNAME/judge0-mcp-server.git
cd judge0-mcp-server

# Install dependencies
npm install

# Configure environment (if using locally)
cp .env.example .env
# Edit .env and add your RAPIDAPI_KEY

📦 Package Information

Package Name: @javaguru/server-judge0

This package uses modern npm scoped naming (the @javaguru/ prefix), following the pattern established by official MCP servers like @modelcontextprotocol/server-filesystem.

Benefits:

✅ Modern scoped package naming following MCP ecosystem conventions
✅ Easy to install with npx -y @javaguru/server-judge0
✅ Platform-agnostic - works with all MCP-compatible clients
✅ Clear ownership under the @javaguru scope

⚙️ Configuration

Claude Desktop

Edit your Claude Desktop configuration file:

macOS: ~/Library/Application Support/Claude/claude_desktop_config.json Windows: %APPDATA%\Claude\claude_desktop_config.json

macOS/Linux:

{
  "mcpServers": {
    "judge0": {
      "command": "npx",
      "args": [
        "-y",
        "@javaguru/server-judge0"
      ],
      "env": {
        "RAPIDAPI_KEY": "your_rapidapi_key_here"
      }
    }
  }
}

Windows:

{
  "mcpServers": {
    "judge0": {
      "command": "cmd",
      "args": [
        "/c",
        "npx",
        "-y",
        "@javaguru/server-judge0"
      ],
      "env": {
        "RAPIDAPI_KEY": "your_rapidapi_key_here"
      }
    }
  }
}

ChatBox

Edit your ChatBox MCP configuration file:

macOS: ~/Library/Application Support/ChatMcp/mcp_server.json Linux: ~/.local/share/ChatMcp/mcp_server.json Windows: %APPDATA%\ChatMcp\mcp_server.json

macOS/Linux:

{
  "mcpServers": {
    "judge0": {
      "command": "npx",
      "args": [
        "-y",
        "@javaguru/server-judge0"
      ],
      "env": {
        "RAPIDAPI_KEY": "your_rapidapi_key_here"
      }
    }
  }
}

Windows:

{
  "mcpServers": {
    "judge0": {
      "command": "cmd",
      "args": [
        "/c",
        "npx",
        "-y",
        "@javaguru/server-judge0"
      ],
      "env": {
        "RAPIDAPI_KEY": "your_rapidapi_key_here"
      }
    }
  }
}

Jan AI

GUI Configuration:

Open Jan AI and go to Settings > Advanced
Enable "Allow All MCP Tool Permission"
Go to Settings > MCP Servers
Click the + icon to add a new server
Enter the following:
macOS/Linux:
- Server Name: judge0
- Command: npx
- Args: -y @javaguru/server-judge0
- Environment Variables:
  - Key: RAPIDAPI_KEY
  - Value: your_rapidapi_key_here
Windows:
- Server Name: judge0
- Command: cmd
- Args: /c npx -y @javaguru/server-judge0
- Environment Variables:
  - Key: RAPIDAPI_KEY
  - Value: your_rapidapi_key_here

Or edit Jan's configuration file directly:

macOS/Linux:

{
  "mcpServers": {
    "judge0": {
      "command": "npx",
      "args": [
        "-y",
        "@javaguru/server-judge0"
      ],
      "env": {
        "RAPIDAPI_KEY": "your_rapidapi_key_here"
      }
    }
  }
}

Windows:

{
  "mcpServers": {
    "judge0": {
      "command": "cmd",
      "args": [
        "/c",
        "npx",
        "-y",
        "@javaguru/server-judge0"
      ],
      "env": {
        "RAPIDAPI_KEY": "your_rapidapi_key_here"
      }
    }
  }
}

LibreChat

Add to your librechat.yaml configuration file:

version: 1.1.5
cache: true

mcpServers:
  judge0:
    type: stdio
    command: npx
    args:
      - -y
      - "@javaguru/server-judge0"
    env:
      RAPIDAPI_KEY: "${RAPIDAPI_KEY}"
    timeout: 30000
    initTimeout: 10000
    serverInstructions: "Execute code in 70+ programming languages securely"

Environment Variables in .env:

RAPIDAPI_KEY=your_rapidapi_key_here

Important: Restart LibreChat after configuration changes.

Zed Editor

Create or edit .zed/mcp.json in your project:

macOS/Linux:

{
  "mcpServers": {
    "judge0": {
      "command": "npx",
      "args": [
        "-y",
        "@javaguru/server-judge0"
      ],
      "env": {
        "RAPIDAPI_KEY": "your_rapidapi_key_here"
      }
    }
  }
}

Windows:

{
  "mcpServers": {
    "judge0": {
      "command": "cmd",
      "args": [
        "/c",
        "npx",
        "-y",
        "@javaguru/server-judge0"
      ],
      "env": {
        "RAPIDAPI_KEY": "your_rapidapi_key_here"
      }
    }
  }
}

VS Code

Open Command Palette (Ctrl+Shift+P) → Run "MCP: Open User Configuration" or edit .vscode/mcp.json:

macOS/Linux:

{
  "mcpServers": {
    "judge0": {
      "command": "npx",
      "args": [
        "-y",
        "@javaguru/server-judge0"
      ],
      "env": {
        "RAPIDAPI_KEY": "your_rapidapi_key_here"
      }
    }
  }
}

Windows:

{
  "mcpServers": {
    "judge0": {
      "command": "cmd",
      "args": [
        "/c",
        "npx",
        "-y",
        "@javaguru/server-judge0"
      ],
      "env": {
        "RAPIDAPI_KEY": "your_rapidapi_key_here"
      }
    }
  }
}

Local Development (Without npx)

If you cloned the repository locally:

{
  "mcpServers": {
    "judge0": {
      "command": "node",
      "args": [
        "/absolute/path/to/judge0-mcp-server/index.js"
      ],
      "env": {
        "RAPIDAPI_KEY": "your_rapidapi_key_here"
      }
    }
  }
}

Note: Always use absolute paths in configuration files.

🛠️ Available Tools

1. `execute_code`

Main execution tool with automatic language detection.

Parameters:

code (string, required) - Source code to execute
language (string, optional) - Programming language (auto-detected if not specified)
stdin (string, optional) - Standard input for the program
timeout (number, optional) - CPU time limit in seconds (max 15)

Example:

{
  "code": "print('Hello, World!')",
  "language": "python"
}

Response:

✅ Execution Successful

Language: Python

Output:
Hello, World!

Performance:
- Execution time: 0.023s
- Memory used: 3.2 MB

2. `execute_python`

Convenient shortcut for Python execution.

Parameters:

code (string, required) - Python code
stdin (string, optional) - Standard input

3. `execute_javascript`

Convenient shortcut for JavaScript (Node.js) execution.

Parameters:

code (string, required) - JavaScript code
stdin (string, optional) - Standard input

4. `list_languages`

Discover all supported programming languages.

Parameters: None

Returns: Complete list of 70+ languages with their aliases and IDs

📚 Supported Languages

Popular Languages (19)

Python 3, JavaScript (Node.js), TypeScript, Java, C, C++, C#, Go, Rust, PHP, Ruby, Swift, Kotlin, R, Bash, SQL, Perl, Scala, Groovy

Functional Languages (7)

Haskell, Clojure, Elixir, Erlang, OCaml, F#, Lisp

And 40+ More!

Use the list_languages tool to see the complete list with all aliases.

💡 Usage Examples

With LibreChat

Create an agent with Judge0 tools enabled:

User: "Write a Python function to calculate fibonacci numbers and run it with n=10"

Agent:

def fibonacci(n):
    if n <= 1:
        return n
    a, b = 0, 1
    for _ in range(n - 1):
        a, b = b, a + b
    return b

result = fibonacci(10)
print(f"Fibonacci(10) = {result}")

[Executes via execute_python tool]

Output:

Fibonacci(10) = 55

With Claude Desktop

Add to your MCP settings and use in conversations:

User: Can you run this JavaScript code?
const arr = [3, 1, 4, 1, 5, 9];
console.log('Sorted:', arr.sort((a, b) => a - b));

Claude will automatically use the Judge0 MCP server to execute the code.

With Zed Editor

Configure in Zed's MCP settings to execute code snippets directly from your editor.

🔧 Environment Variables

The server supports two deployment modes:

RapidAPI Mode (Default)

{
  "env": {
    "RAPIDAPI_KEY": "your_rapidapi_key_here"
  }
}

FREE tier: 50 executions/day
Paid plans: Starting at $50/month for 30,000 executions
Get your key: RapidAPI Judge0

Self-Hosted Mode (Unlimited FREE)

For unlimited usage, run your own Judge0 instance:

# Clone Judge0
git clone https://github.com/judge0/judge0.git
cd judge0

# Start with Docker Compose
docker-compose up -d

# API available at: http://localhost:2358

Then configure your MCP client:

macOS/Linux:

{
  "mcpServers": {
    "judge0": {
      "command": "npx",
      "args": ["-y", "@javaguru/server-judge0"],
      "env": {
        "JUDGE0_BASE_URL": "http://localhost:2358"
      }
    }
  }
}

Windows:

{
  "mcpServers": {
    "judge0": {
      "command": "cmd",
      "args": ["/c", "npx", "-y", "@javaguru/server-judge0"],
      "env": {
        "JUDGE0_BASE_URL": "http://localhost:2358"
      }
    }
  }
}

Note: When using self-hosted, you don't need RAPIDAPI_KEY.

🔒 Security

Sandboxing

All code execution happens in Judge0's secure sandbox:

✅ Process Isolation - Each execution in separate container
✅ Resource Limits - CPU time (max 15s), Memory (128MB default)
✅ Network Restrictions - No external network access
✅ File System Isolation - Limited sandbox directory
✅ Automatic Cleanup - Containers destroyed after execution

Best Practices

Set appropriate timeouts for long-running code
Monitor usage via RapidAPI dashboard
Use self-hosted for sensitive code
Validate code before execution
Review execution results

💰 Pricing

RapidAPI FREE Tier

50 executions/day
No credit card required
Perfect for personal use and testing

RapidAPI Paid Plans

$50/month: 30,000 executions
Pay-as-you-go: $5 per 1,000 executions

Self-Hosted

FREE unlimited usage
Requires Docker infrastructure
Full control and privacy

🧪 Testing

Manual Test

# Set your API key
export RAPIDAPI_KEY="your_key_here"

# Run the server
npm start

Expected output:

Judge0 MCP Server starting...
✓ Connected to Judge0 API successfully
✓ Supports 70+ programming languages
✓ Ready to execute code via MCP
Judge0 MCP Server running

Integration Test

Use with any MCP client to test code execution across different languages.

📖 Documentation

Installation Guide - Detailed setup instructions
API Reference - Complete tool documentation
Language Support - All 70+ languages with examples
Troubleshooting - Common issues and solutions
Self-Hosting Guide - Run your own Judge0

🤝 Compatible MCP Clients

✅ Claude Desktop - Anthropic's desktop app
✅ ChatBox - Multi-platform AI chat client
✅ Jan AI - Open-source ChatGPT alternative
✅ LibreChat - Multi-model AI chat platform
✅ Zed - High-performance code editor
✅ VS Code - With MCP extension
✅ Any MCP-compatible application

🐛 Troubleshooting

Cannot connect to Judge0 API

Solution:

Verify RAPIDAPI_KEY in .env
Check API key validity on RapidAPI dashboard
Ensure you're subscribed to Judge0 CE (FREE tier)

Rate limit exceeded

Solution:

Wait 24 hours for limit reset
Upgrade to paid plan
Use self-hosted Judge0 (unlimited)

Unknown language error

Solution:

Use list_languages tool to see supported languages
Check language name spelling
Try common aliases (e.g., "py" for Python)

For more issues, see Troubleshooting Guide

🤝 Contributing

Contributions are welcome! Please read CONTRIBUTING.md for guidelines.

Ways to Contribute

🐛 Report bugs
✨ Suggest features
📖 Improve documentation
🌍 Add language support
🧪 Write tests
🔧 Fix issues

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

🙏 Acknowledgments

Judge0 - Excellent code execution platform
Model Context Protocol - Tool integration standard
LibreChat - Inspiration and use case
Community Contributors - Thank you!

📊 Stats

Languages Supported: 70+
MCP Tools: 4
Lines of Code: ~1,500
Documentation: Comprehensive
License: MIT
Status: Production Ready

🔗 Links

Repository: https://github.com/YOUR_USERNAME/judge0-mcp-server
Issues: https://github.com/YOUR_USERNAME/judge0-mcp-server/issues
Judge0 API: https://ce.judge0.com/
RapidAPI: https://rapidapi.com/judge0-official/api/judge0-ce
MCP Specification: https://modelcontextprotocol.io/

⭐ Show Your Support

If you find this project useful, please consider:

⭐ Starring the repository
🐛 Reporting bugs
💡 Suggesting features
🤝 Contributing code
📢 Sharing with others

Built with ❤️ for the MCP and AI community

Ready to execute code? Get started now! 🚀

Published

Vulnerabilities

Links

Maintainers

Keywords

Readme

Judge0 MCP Server

✨ Features

🚀 Quick Start

Prerequisites

Installation

📦 Package Information

⚙️ Configuration

Claude Desktop

ChatBox

Jan AI

LibreChat

Zed Editor

VS Code

Local Development (Without npx)

🛠️ Available Tools

1. execute_code

2. execute_python

3. execute_javascript

4. list_languages

📚 Supported Languages

Popular Languages (19)

Functional Languages (7)

And 40+ More!

💡 Usage Examples

With LibreChat

With Claude Desktop

With Zed Editor

🔧 Environment Variables

RapidAPI Mode (Default)

Self-Hosted Mode (Unlimited FREE)

🔒 Security

Sandboxing

Best Practices

💰 Pricing

RapidAPI FREE Tier

RapidAPI Paid Plans

Self-Hosted

🧪 Testing

Manual Test

Integration Test

📖 Documentation

🤝 Compatible MCP Clients

🐛 Troubleshooting

Cannot connect to Judge0 API

Rate limit exceeded

Unknown language error

🤝 Contributing

Ways to Contribute

📄 License

🙏 Acknowledgments

📊 Stats

🔗 Links

⭐ Show Your Support

1. `execute_code`

2. `execute_python`

3. `execute_javascript`

4. `list_languages`