# Lean: The Open-Source Algorithmic Trading Engine by QuantConnect This repository profile is provided by osrepos.com, an open source repository discovery platform. Source: osrepos.com Repository profile: https://osrepos.com/repo/quantconnect-lean Generated for open source discovery and AI-assisted research. Lean is a professional-caliber, event-driven algorithmic trading engine developed by QuantConnect, supporting strategies in Python and C#. It provides a robust platform for backtesting and live trading across various financial markets. With its modular design and comprehensive features, Lean empowers quantitative developers to build and deploy sophisticated trading algorithms. GitHub: https://github.com/QuantConnect/Lean OSRepos URL: https://osrepos.com/repo/quantconnect-lean ## Summary Lean is a professional-caliber, event-driven algorithmic trading engine developed by QuantConnect, supporting strategies in Python and C#. It provides a robust platform for backtesting and live trading across various financial markets. With its modular design and comprehensive features, Lean empowers quantitative developers to build and deploy sophisticated trading algorithms. ## Topics - algorithmic-trading-engine - finance - python - c-sharp - quantconnect - trading-platform - backtesting - forex ## Repository Information Last analyzed by OSRepos: Tue Jun 02 2026 13:14:06 GMT+0100 (Western European Summer Time) Detail views: 38 GitHub clicks: 21 ## Safety Notice OSRepos shares public repositories for knowledge and discovery only. Review source code, dependencies, licenses, and security implications before running or installing anything. ## Content ## Introduction Lean is an advanced, open-source algorithmic trading engine crafted by QuantConnect. Designed with elegant engineering and deep quant concept modeling in mind, it offers a powerful framework for developing, backtesting, and live trading algorithms. Supporting both Python and C#, Lean is an event-driven platform that comes with out-of-the-box alternative data and live-trading capabilities, making it a versatile tool for quantitative finance. The engine's modular architecture ensures that each component is pluggable and customizable, providing flexibility for developers to tailor the platform to their specific needs. It includes models for all major plug-in points, facilitating extensive customization and integration. ## Installation For most users, the recommended way to get started with Lean is through the LEAN CLI, which is prebuilt and runs on all platforms. To install the CLI: bash pip install lean For local development and direct source code access, you can clone the repository: bash git clone https://github.com/QuantConnect/Lean.git cd Lean Detailed installation guides for specific operating systems are available: ### macOS 1. Install [Visual Studio Code for Mac](https://code.visualstudio.com/download "Visual Studio Code for Mac" target="_blank"). 2. Install the [C# Dev Kit extension](https://marketplace.visualstudio.com/items?itemName=ms-dotnettools.csdevkit "C# Dev Kit extension" target="_blank"). 3. Install [.NET 9 SDK](https://dotnet.microsoft.com/en-us/download/dotnet/9.0 ".NET 9 SDK" target="_blank"). 4. Build the solution: bash dotnet build 5. Run the solution: bash cd Launcher/bin/Debug dotnet QuantConnect.Lean.Launcher.dll ### Linux (Debian, Ubuntu) 1. Install [.NET 9](https://docs.microsoft.com/en-us/dotnet/core/install/linux ".NET 9" target="_blank"). 2. Compile Lean Solution: bash dotnet build QuantConnect.Lean.sln 3. Run Lean: bash cd Launcher/bin/Debug dotnet QuantConnect.Lean.Launcher.dll ### Windows 1. Install [Visual Studio](https://www.visualstudio.com/en-us/downloads/download-visual-studio-vs.aspx "Visual Studio" target="_blank"). 2. Open `QuantConnect.Lean.sln` in Visual Studio. 3. Build the solution (this should trigger NuGet package restore). 4. Press `F5` to run. For comprehensive Python support details, refer to the [Algorithm.Python project](https://github.com/QuantConnect/Lean/tree/master/Algorithm.Python#quantconnect-python-algorithm-project "Algorithm.Python project" target="_blank"). ## Examples The LEAN CLI simplifies common tasks for managing and running your algorithmic trading projects. Here are some examples of commands you can use: * **Create a new project:** bash lean project-create * **Run a local Jupyter Lab environment:** bash lean research * **Backtest a project locally:** bash lean backtest * **Optimize a project locally:** bash lean optimize * **Start live trading a project locally:** bash lean live For a full list of commands, download the [LEAN CLI Cheat Sheet](https://cdn.quantconnect.com/i/tu/cli-cheat-sheet.pdf "LEAN CLI Cheat Sheet" target="_blank"). ## Why Use Lean? Lean stands out as a premier choice for algorithmic trading due to several key advantages: * **Professional Caliber:** It's an event-driven platform built for serious quant development, offering robust features for complex strategies. * **Multi-Language Support:** Develop your algorithms in either Python or C#, leveraging the strengths of both languages. * **Modular and Customizable:** Its highly modular design allows for extensive customization, enabling developers to integrate custom components and data sources. * **Comprehensive Functionality:** Supports backtesting, optimization, and live trading across various asset classes, including stocks, options, forex, and futures. * **Active Community and Support:** Benefit from a vibrant community, extensive documentation, and dedicated forums for assistance and collaboration. * **Local-Cloud Hybrid Development:** Seamlessly develop and debug strategies locally while integrating with cloud services for deployment and scaling. ## Links * **Lean Home Page:** [https://www.lean.io/](https://www.lean.io/ "Lean Home Page" target="_blank") * **Documentation:** [https://www.lean.io/docs/](https://www.lean.io/docs/ "Lean Documentation" target="_blank") * **GitHub Repository:** [https://github.com/QuantConnect/Lean](https://github.com/QuantConnect/Lean "GitHub Repository" target="_blank") * **LEAN Forum:** [https://www.quantconnect.com/forum/discussions/1/lean](https://www.quantconnect.com/forum/discussions/1/lean "LEAN Forum" target="_blank") * **Discord Chat:** [https://www.quantconnect.com/discord](https://www.quantconnect.com/discord "Discord Chat" target="_blank") * **Docker Hub:** [https://hub.docker.com/orgs/quantconnect/repositories](https://hub.docker.com/orgs/quantconnect/repositories "Docker Hub" target="_blank") * **NuGet:** [https://www.nuget.org/profiles/jaredbroad](https://www.nuget.org/profiles/jaredbroad "NuGet" target="_blank")