An open source fork of Windows Live Writer

:cake: Cake (C# Make) is a cross platform build automation system.

Build Mobile, Desktop and WebAssembly apps with C# and XAML. Today. Open source and professionally supported.

Mono open source ECMA CLI, C# and .NET implementation.

AutoFixture is an open source library for .NET designed to minimize the 'Arrange' phase of your unit tests in order to maximize maintainability. Its primary goal is to allow developers to focus on what is being tested rather than how to setup the test scenario, by making it easier to create object graphs containing test data.

Lean Algorithmic Trading Engine by QuantConnect (Python, C#)

Every programmer needs a rubberduck. COM add-in for the VBA & VB6 IDE (VBE).

Accept Bitcoin payments. Free, open-source & self-hosted, Bitcoin payment processor.

One framework for creating powerful cross-platform games.

ML.NET is an open source and cross-platform machine learning framework for .NET.

The mobile app vault (iOS and Android).

The best C# command line parser that brings standardized *nix getopt style, for .NET. Includes F# support

ASP.NET Core is a cross-platform .NET framework for building modern cloud-based web applications on Windows, Mac, or Linux.

.NET core API Gateway

EF Core is a modern object-database mapper for .NET. It supports LINQ queries, change tracking, updates, and schema migrations.

xUnit.net is a free, open source, community-focused unit testing tool for .NET.

A cross-platform plotting library for .NET

Linq to database provider.

Powerful .NET library for benchmarking

A wrapper executable that can run any executable as a Windows service, in a permissive license.

Google's Material Design in XAML & WPF, for C# & VB.Net.

Highly performant and modular controls for node-based editors designed for data-binding and MVVM.

Open Source Web Application Framework for ASP.NET Core

.NET for Apache® Spark™ makes Apache Spark™ easily accessible to .NET developers.

💫 NClient is an automatic type-safe .Net HTTP client that allows you to call web service API methods using annotated interfaces or controllers without boilerplate code.