.NET

DotNettyAzure/DotNetty

A port of Netty, providing an asynchronous event-driven network application framework for high-performance protocol servers and clients in .NET.

SuperSocketkerryjiang/SuperSocket

A high-performance, extensible socket server application framework for .NET supporting TCP, UDP, and WebSocket protocols.

Cakecake-build/cake

A cross-platform build automation system with a C# DSL for compiling, testing, packaging, and more.

Extended WPF Toolkit™xceedsoftware/wpftoolkit

A comprehensive collection of free WPF controls, components, and utilities for building modern Windows desktop applications.

OneOfmcintyre321/OneOf

F#-like discriminated unions for C# with exhaustive compile-time matching, providing a type-safe alternative to polymorphism and exceptions.

Mapperlyriok/mapperly

A .NET source generator for generating high-performance object mappings with no runtime reflection.

WinAppDriverMicrosoft/WinAppDriver

A service enabling Selenium-like UI test automation for Windows desktop applications (UWP, WinForms, WPF, Win32).

EFCore.BulkExtensionsborisdj/EFCore.BulkExtensions

Entity Framework Core extensions for high-performance bulk CRUD operations (Insert, Update, Delete, Read, Upsert, Sync) on SQL Server, PostgreSQL, MySQL, SQLite, and Oracle.

Eto.Formspicoe/Eto

A cross-platform desktop and mobile UI framework for .NET that uses native toolkits for a single codebase.

MVVMCrossMvvmCross/MvvmCross

A cross-platform MVVM framework for .NET, enabling code sharing across Android, iOS, macOS, tvOS, WPF, and WinUI.

SharpZipLibicsharpcode/SharpZipLib

A pure C# library for Zip, GZip, Tar, and BZip2 compression and decompression on the .NET platform.

PuppeteerSharpkblok/puppeteer-sharp

A .NET port of the official Node.js Puppeteer API for headless browser automation.

Scribanlunet-io/scriban

A fast, powerful, safe and lightweight scripting language and engine for .NET, designed for text templating and general scripting.

MoreLINQmorelinq/MoreLINQ

A library that extends LINQ to Objects with over 100 additional methods for advanced sequence manipulation.

MoreLinqMoreLinq/MoreLinq

A library that extends LINQ to Objects with over 100 additional methods for advanced sequence manipulation.

Nukenuke-build/nuke

A cross-platform build automation system for .NET that uses C# for build definitions instead of YAML or scripts.

Math.NET Numericsmathnet/mathnet-numerics

An open-source numerical library for .NET and Mono providing algorithms for scientific computing, linear algebra, statistics, and more.

AsyncExStephenCleary/AsyncEx

A comprehensive helper library for async/await in .NET, providing async-compatible coordination primitives like AsyncLock.

npgsqlnpgsql/npgsql

The open-source .NET data provider for PostgreSQL, enabling high-performance database connectivity and operations.

Npgsqlnpgsql/Npgsql

The open-source .NET data provider for PostgreSQL, enabling high-performance database connectivity and operations.

Event Sourcing .NEToskardudycz/EventSourcing.NetCore

A comprehensive collection of tutorials, samples, and resources for implementing Event Sourcing and CQRS in .NET using Marten and EventStoreDB.

System.CommandLinedotnet/command-line-api

A .NET library for parsing command-line arguments, building CLI applications, and rendering terminal output.

Elasticsearch .NETelastic/elasticsearch-net

The official strongly-typed .NET client library for Elasticsearch, maintained by Elastic.

LLamaSharpSciSharp/LLamaSharp

A C#/.NET library for efficient local inference of LLaMA and other large language models, based on llama.cpp.

Facepunch.SteamworksFacepunch/Facepunch.Steamworks

A modern, idiomatic C# Steamworks wrapper for Unity and .NET, providing a fully-featured, open-source alternative to existing implementations.

AutoFixtureAutoFixture/AutoFixture

An open source .NET library that automates test data generation to minimize unit test setup and maximize maintainability.

OxyPlotoxyplot/oxyplot

A cross-platform plotting library for .NET that creates charts and graphs in desktop, web, and mobile applications.

BlazoriseMegabit/Blazorise

A source-available Blazor UI component library with a consistent API across Bootstrap, Tailwind, Bulma, Material, AntDesign, and Fluent UI.

Blazorisestsrki/Blazorise

A source-available Blazor UI component library with a consistent API across Bootstrap, Tailwind, Bulma, Material, AntDesign, and Fluent UI.

OpenTKopentk/opentk

A fast, low-level C# binding for OpenGL, OpenAL, and OpenCL with cross-platform windowing, input, and math libraries.

Discord.NetRogueException/Discord.Net

An unofficial .NET wrapper for the Discord API, enabling developers to build Discord bots and integrations.

FluentMigratorfluentmigrator/fluentmigrator

A .NET migration framework that manages database schema changes using C# classes instead of SQL scripts.

LibGit2Sharplibgit2/libgit2sharp

A .NET wrapper for libgit2 that provides native Git functionality to managed applications.

VerifyVerifyTests/Verify

A snapshot testing tool for .NET that simplifies assertions of complex data models and documents.

RoslynatorJosefPihrt/Roslynator

A comprehensive set of code analysis tools, refactorings, and client libraries for C# development, built on the Roslyn compiler platform.

TickerQArcenox-co/TickerQ

A fast, reflection-free background task scheduler for .NET with source generators, EF Core/Redis persistence, cron execution, and a real-time dashboard.