Browse free open source C# Frameworks and projects below. Use the toggles on the left to filter open source C# Frameworks by OS, license, language, programming language, and project status.

  • MongoDB Atlas runs apps anywhere Icon
    MongoDB Atlas runs apps anywhere

    Deploy in 115+ regions with the modern database for every enterprise.

    MongoDB Atlas gives you the freedom to build and run modern applications anywhere—across AWS, Azure, and Google Cloud. With global availability in over 115 regions, Atlas lets you deploy close to your users, meet compliance needs, and scale with confidence across any geography.
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  • Build Agents and Models on One Platform Icon
    Build Agents and Models on One Platform

    Everything you need to build production-ready agents and models. Access 200+ Google and third-party AI models and tools.

    Gemini Enterprise Agent Platform is Google Cloud's comprehensive platform for developers to build, scale, govern, and optimize agents and models. Choose from Google's most advanced models and third-party models like Anthropic's Claude Model Family.
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  • 1
    BepInEx

    BepInEx

    Unity / XNA game patcher and plugin framework

    Unity / XNA game patcher and plugin framework. BepInEx is a plugin / modding framework for Unity Mono, IL2CPP, and .NET framework games (XNA, FNA, MonoGame, etc.) Stable builds are released once a new iteration of BepInEx is considered feature-complete. They have the least bugs, but some newest features might not be available. Bleeding edge builds are available on BepisBuilds. Bleeding edge builds are always the latest builds of the source code. Thus they are the opposite to stable builds: they have the newest features and bugfixes available, but usually tend to be the most buggy. Therefore you should use bleeding edge builds only if you are asked to or if you want to preview the upcoming version of BepInEx. Some games require some additional changes in order to work around specific limitations of different Unity versions.
    Downloads: 891 This Week
    Last Update:
    See Project
  • 2
    PowerShell

    PowerShell

    Command-line shell and scripting language built on .NET

    Powershell is a cross-platform, task-based command-line shell and scripting language that helps rapidly automate tasks that manage operating systems (Linux, macOS and Windows) and processes. It works well with existing tools and is optimized for dealing with structured data, REST APIs and object models. PowerShell was developed by Microsoft as a task management and configuration management framework. Powershell is designed to let you manage computers from the command line and improve the command-line and scripting environment.
    Downloads: 521 This Week
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  • 3
    StabilityMatrix

    StabilityMatrix

    Multi-Platform Package Manager for Stable Diffusion

    StabilityMatrix is a project that helps organize, evaluate, and compare generative AI models and their behavior across prompts, datasets, or configuration settings. It provides a framework to run experiments systematically—capturing inputs, model configurations, outputs, and metrics—so researchers and practitioners can reason about differences in quality, robustness, and failure modes. The repository often bundles tooling for automated prompt sweeping, scoring heuristics (such as diversity, coherence, or task-specific metrics), and visualization helpers to make comparisons interpretable. This approach is useful for model selection, prompt engineering, and benchmarking new checkpoints against baseline models under reproducible conditions. By turning ad-hoc tests into tracked experiments, StabilityMatrix reduces bias, surfaces subtle regressions, and accelerates iteration when tuning generative systems.
    Downloads: 143 This Week
    Last Update:
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  • 4
    Selenium

    Selenium

    Browser automation framework and ecosystem

    Selenium automates browsers. That's it! What you do with that power is entirely up to you. Primarily it is for automating web applications for testing purposes, but is certainly not limited to just that. Boring web-based administration tasks can (and should) also be automated as well. If you want to create robust, browser-based regression automation suites and tests, scale and distribute scripts across many environments, then you want to use Selenium WebDriver, a collection of language specific bindings to drive a browser - the way it is meant to be driven. If you want to create quick bug reproduction scripts, create scripts to aid in automation-aided exploratory testing, then you want to use Selenium IDE; a Chrome and Firefox add-on that will do simple record-and-playback of interactions with the browser. If you want to scale by distributing and running tests on several machines and manage multiple environments from a central point.
    Downloads: 125 This Week
    Last Update:
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  • Custom VMs From 1 to 96 vCPUs With 99.95% Uptime Icon
    Custom VMs From 1 to 96 vCPUs With 99.95% Uptime

    General-purpose, compute-optimized, or GPU/TPU-accelerated. Built to your exact specs.

    Live migration and automatic failover keep workloads online through maintenance. One free e2-micro VM every month.
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  • 5
    mpv.net

    mpv.net

    mpv.net is a modern media player for Windows that works just like mpv

    mpv.net is a modern desktop media player for Windows based on the popular mpv player. mpv.net is designed to be mpv compatible, almost all mpv features are available because they are all contained in libmpv, this means the official mpv manual applies to mpv.net. mpv focuses on the usage of the command line and the terminal, mpv.net retains the ability to be used from the command line and the terminal and adds a modern Windows GUI on top of it. Video output that is capable of many features loved by videophiles, such as video scaling with popular high-quality algorithms, color management, frame timing, interpolation, HDR, and more. Leverages the FFmpeg hwaccel APIs to support DXVA2 video decoding acceleration. mpv.net is based on libmpv which offers a straightforward C API that was designed from the ground up to make mpv usable as a library and facilitate easy integration into other applications. mpv is like VLC not based on DirectShow or Media Foundation.
    Downloads: 82 This Week
    Last Update:
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  • 6
    Grassroots DICOM

    Grassroots DICOM

    Cross-platform DICOM implementation

    Grassroots DiCoM is a C++ library for DICOM medical files. It is accessible from Python, C#, Java and PHP. It supports RAW, JPEG, JPEG 2000, JPEG-LS, RLE and deflated transfer syntax. It comes with a super fast scanner implementation to quickly scan hundreds of DICOM files. It supports SCU network operations (C-ECHO, C-FIND, C-STORE, C-MOVE). PS 3.3 & 3.6 are distributed as XML files. It also provides PS 3.15 certificates and password based mecanism to anonymize and de-identify DICOM datasets.
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    Downloads: 253 This Week
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  • 7
    .NET Runtime

    .NET Runtime

    Cross-platform runtime for cloud, mobile, desktop, and IoT apps

    .NET is a free, cross-platform, open source developer platform for building many different types of applications. With .NET, you can use multiple languages, editors, and libraries to build for web, mobile, desktop, games, and IoT. You can write .NET apps in C#, F#, or Visual Basic. C# is a simple, modern, object-oriented, and type-safe programming language. F# is a cross-platform, open-source, functional programming language for .NET. It also includes object-oriented and imperative programming. Visual Basic is an approachable language with a simple syntax for building type-safe, object-oriented apps. Whether you're working in C#, F#, or Visual Basic, your code will run natively on any compatible OS. Different .NET implementations handle the heavy lifting for you.
    Downloads: 40 This Week
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  • 8
    CefSharp

    CefSharp

    .NET bindings for the Chromium embedded framework

    CefSharp is an easy way to embed a full-featured standards-compliant web browser into your C# or VB.NET app. CefSharp has browser controls for WinForms and WPF apps, and a headless (offscreen) version for automation projects too. CefSharp is based on Chromium Embedded Framework, the open source version of Google Chrome. CefSharp embraces modern web standards, and supports HTML5, JavaScript, CSS3 and HTML5 audio/video elements. 3D content is supported via WebGL which uses OpenGL/DirectX for hardware accelerated rendering. CefSharp includes embedded modules for PDF, web page printing and the WebKit Inspector (developer tools). CefSharp has no external dependencies, and the full build of CefSharp only adds ~80 MB to your app. See the CefSharp.MinimalExample project for ready-to-compile minimal example apps built with CefSharp. Within the projects source there are more complicated example projects.
    Downloads: 34 This Week
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  • 9
    Obfuscar

    Obfuscar

    Open source obfuscation tool for .NET assemblies

    Obfuscar is an open-source .NET obfuscator released under MIT license. It provides basic obfuscation features that help secure secrets in a .NET assembly. An obfuscation tool designed for most .NET developers. Hide everything private, while keep everything public. You can achieve such simply via default settings. Hide class/method/property/event names that you don't want to expose. This is irreversible. String contents can be compressed so that end users won't easily learn them. However, this is reversible by certain tools.
    Downloads: 26 This Week
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  • Go from Code to Production URL in Seconds Icon
    Go from Code to Production URL in Seconds

    Cloud Run deploys apps in any language instantly. Scales to zero. Pay only when code runs.

    Skip the Kubernetes configs. Cloud Run handles HTTPS, scaling, and infrastructure automatically. Two million requests free per month.
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  • 10
    AvaloniaILSpy

    AvaloniaILSpy

    Avalonia-based .NET Decompiler (port of ILSpy)

    This is a cross-platform version of ILSpy built with Avalonia. Search for types/methods/properties (substring). Hyperlink-based type/method/property navigation. Extensible via MEF Extensibility (Check out TestPlugin folder). Note: This is not compatible with ILSpy Plugins. Grab artifacts from the latest master CI build. This includes Linux, Mac and Windows.
    Downloads: 24 This Week
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  • 11

    Emgu CV

    Emgu CV is a cross platform .Net wrapper for OpenCV

    Emgu CV is a cross platform .Net wrapper to the OpenCV image processing library. Allowing OpenCV functions to be called from .NET compatible languages such as C#, VB, VC++, IronPython etc. The wrapper can be compiled in Mono and run on Windows, Linux, Mac OS X, iPhone, iPad and Android devices.
    Downloads: 110 This Week
    Last Update:
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  • 12
    dotnet sdk

    dotnet sdk

    Core functionality needed to create .NET Core projects

    Core functionality needed to create .NET Core projects, that is shared between Visual Studio and CLI. There are no fees or licensing costs, including for commercial use. .NET is open-source and cross-platform, with free development tools for Windows, Linux, and macOS. .NET is supported by Microsoft. Microsoft ships official releases that are built and tested on Microsoft-maintained servers in Azure and supported just like any Microsoft product. .NET is open source and we are very thankful for the many contributions it receives from the community. To test your locally built SDK, run eng\dogfood.cmd after building. That script starts a new Powershell with the environment configured to redirect SDK resolution to your build.
    Downloads: 23 This Week
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  • 13
    GitVersion

    GitVersion

    From git log to SemVer in no time

    GitVersion is free to use, improve, contribute and distribute. Source code is available on GitHub under MIT license. GitVersion is built for many different use-cases and workflows, so whether you use Mainline, Git Flow or GitHub Flow, GitVersion has you covered. Gitversion is highly configurable and can be made to support your specific versioning scheme, almost regardless of what it may be. Expose version variables in different formats to the tools you use. Use GitVersion locally or in a build pipeline with TeamCity, AppVeyor, Jenkins or any of the other supported build servers. GitVersion is a tool that generates a Semantic Version number based on your Git history. The version number generated from GitVersion can then be used for various different purposes. GitVersion can be used in a Continuous Server pipeline to generate a version number that both labels the build itself and makes the different version variables available to the rest of the build pipeline.
    Downloads: 22 This Week
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  • 14
    Pokemon Unity

    Pokemon Unity

    A framework to build Pokémon RPG games

    A framework to build Pokémon RPG games. I use IIcolour Spectrum's original Pokemon Unity as a base with Herbertmilhomme's framework. So far, this project use wrapper ( Legacy <=> Framework ), and in the future, I want to remove the wrapper. This project is playable, but it has some issues and some features are disabled. Use Unity Hub or Editor to import this project's folder (/Pokemon Unity). Build and run the project. There are also demos for Windows, Linux, and Mac zipped in Releases!
    Downloads: 22 This Week
    Last Update:
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  • 15
    CoreCLR

    CoreCLR

    Runtime for .NET Core

    CoreCLR is the runtime for .NET Core, an open source, general purpose development platform maintained by Microsoft and the .NET community. It is a cross-platform runtime for cloud, IoT, and desktop apps and includes a just-in-time compiler called RyuJIT.
    Downloads: 19 This Week
    Last Update:
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  • 16
    Pomelo.EntityFrameworkCore.MySql

    Pomelo.EntityFrameworkCore.MySql

    Entity Framework Core provider for MySQL and MariaDB

    Entity Framework Core provider for MySQL and MariaDB built on top of MySqlConnector. Pomelo.EntityFrameworkCore.MySql is the most popular Entity Framework Core provider for MySQL-compatible databases. It supports EF Core up to its latest version and uses MySqlConnector for high-performance database server communication. Pomelo.EntityFrameworkCore.MySql is tested against all actively maintained versions of MySQL and MariaDB. Older versions (e.g. MySQL 5.6) and other server implementations (e.g. Amazon Aurora) are usually compatible to a high degree as well, but are not tested as part of our CI. Check out our Integration Tests for an example repository that includes an ASP.NET Core MVC Application.
    Downloads: 18 This Week
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  • 17
    ChilliCream GraphQL Platform

    ChilliCream GraphQL Platform

    Welcome to the home of the Hot Chocolate GraphQL server for .NET

    Welcome to the home of the Hot Chocolate GraphQL server for .NET, the Strawberry Shake GraphQL client for .NET and Banana Cake Pop awesome Monaco-based GraphQL IDE. The ChilliCream GraphQL Platform, at its core, is a new way to create powerful Backends. HotChocolate, our .NET GraphQL server, connects any service or data source and creates a cohesive service to offer your consumers a unified API.
    Downloads: 17 This Week
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  • 18
    reko

    reko

    Reko is a binary decompiler

    Reko (Swedish: "decent, obliging") is a decompiler for machine code binaries. This project is freely available under the GNU General Public License. The project consists of front ends, core decompiler engine, and back ends to help it achieve its goals. A command line, a Windows GUI, and a ASP.NET front end exist at the time of writing. The decompiler engine receives inputs from the front ends in the form of either individual executable files or decompiler project files. Reko project files contain additional information about a binary file, helpful to the decompilation process or for formatting the output. The decompiler engine then proceeds to analyze the input binary. Reko has the ambition of supporting decompilation of various processor architectures and executable file formats with minimal user intervention. For a complete list, see the supported binaries page.
    Downloads: 17 This Week
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  • 19
    NHibernate
    .NET port of the excellent Java Hibernate which provides Object/Relational mapping to persist objects in a relational database.
    Downloads: 69 This Week
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  • 20
    ASP.NET API Versioning

    ASP.NET API Versioning

    Libraries which add service API versioning to ASP.NET Web API

    ASP.NET API versioning gives you a powerful, but easy-to-use method for adding API versioning semantics to your new and existing REST services built with ASP.NET. The API versioning extensions define simple metadata attributes and conventions that you use to describe which API versions are implemented by your services. You don't need to learn any new routing concepts or change the way you implement your services in ASP.NET today. The default API versioning configuration is compliant with the versioning semantics outlined by the Microsoft REST Guidelines. There are also a number of customization and extension points available to support transitioning services that may not have supported API versioning in the past or supported API versioning with semantics that are different from the Microsoft REST versioning guidelines.
    Downloads: 15 This Week
    Last Update:
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  • 21
    Json.NET

    Json.NET

    A popular high-performance JSON framework for .NET

    Serialize and deserialize any .NET object with Json.NET's powerful JSON serializer. Create, parse, query and modify JSON using Json.NET's JObject, JArray and JValue objects. Query JSON with an XPath-like syntax. 50% faster than DataContractJsonSerializer, and 250% faster than JavaScriptSerializer. Json.NET makes the simple easy and the complex possible. If you need it, Json.NET supports converting between XML and JSON. Json.NET is open source software and is completely free for commercial use. Json.NET supports Windows, MacOS, Linux, Mono, and Xamarin. Over 1 billion downloads and counting, Json.NET is the number one library on NuGet. Json.NET documentation is the first place to go for help. It includes over 100 code samples. Json.NET is open source under the MIT license and is free for commercial use.
    Downloads: 14 This Week
    Last Update:
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  • 22
    Paket

    Paket

    A dependency manager for .NET with support for NuGet packages and Git

    A dependency manager for .NET with support for NuGet packages and Git repositories. NuGet does not separate out the concept of transitive dependencies. If you install a package into your project and that package has further dependencies then all transitive packages are included in the packages.config. There is no way to tell which packages are only transitive dependencies. Even more importantly: If two packages reference conflicting versions of a package, NuGet will silently take the latest version (read more). You have no control over this process. Paket on the other hand maintains this information on a consistent and stable basis within the paket.lock file in the solution root. This file, together with the paket.dependencies file enables you to determine exactly what's happening with your dependencies.
    Downloads: 13 This Week
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  • 23
    Seal Report

    Seal Report

    Database Reporting Tool and Tasks (.Net)

    Seal Report is an open-source tool for the generation of daily reports from any database. It offers a complete framework for producing dynamic reports and dashboards, with a focus on simplicity and ease of use.
    Downloads: 11 This Week
    Last Update:
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  • 24
    JPPF

    JPPF

    The open source grid computing solution

    JPPF makes it easy to parallelize computationally intensive tasks and execute them on a Grid.
    Downloads: 51 This Week
    Last Update:
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  • 25
    reacTIVision
    reacTIVision is a computer vision framework for the fast and robust tracking of markers attached on physical objects, and the creation of multi-touch surfaces. It was designed for the rapid development of table-based tangible user interfaces.
    Downloads: 47 This Week
    Last Update:
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