Open Source C# Projects
C# is a modern, statically typed programming language used to build web services, desktop applications, games, command-line tools, and cloud software. Its features support clear, maintainable code and help catch many errors during development. With a managed runtime and broad ecosystem of libraries, C# can serve both small utilities and large applications across different operating systems and deployment environments.
Open source C# tools include application frameworks, libraries, developer utilities, servers, and games. When choosing one, consider its license, documentation, release history, community activity, supported runtime versions, platform requirements, and compatibility with your existing code. C# projects can be useful to individual developers, teams, organizations, and learners building or maintaining software in the language.
25 repositories · updated October 3, 2026
mcp-server-excel: Automate Microsoft Excel with AI
mcp-server-excel lets AI assistants and coding agents automate the real Microsoft Excel application through MCP or a CLI. It suits Windows users who need workbook operations that file parsers cannot perform, such as refreshing Power Query or running VBA.
awesome-dotnet: Discover .NET Libraries and Tools
A community-maintained, categorized directory of .NET libraries, tools, frameworks, and software. Use it to explore options across areas such as APIs, databases, testing, desktop development, and machine learning.
OpenRA: Play and Mod Classic Westwood RTS Games
OpenRA is a cross-platform C# engine for playing and creating real-time strategy games inspired by early Westwood classics. It supports distributed reimaginings of Red Alert, Tiberian Dawn, and Dune 2000, plus custom maps and mods.
OfficeCLI: Create and Edit Office Files from the Command Line
OfficeCLI is a cross-platform CLI for AI agents and developers to create, read, edit, and validate Word, Excel, and PowerPoint files. It combines structured commands, JSON output, and built-in document previews in a self-contained binary.
QuestPDF: Generate PDF Documents with C#
QuestPDF is a C# library for creating structured PDF documents through a fluent, component-based API. It suits .NET developers building reports, invoices, and other data-driven documents without relying on HTML-to-PDF conversion.
Lean: Build and Run Algorithmic Trading Strategies
QuantConnect Lean is an event-driven engine for developing, backtesting, and live trading algorithmic strategies across financial markets. It suits quantitative developers who want a modular C# engine with Python support and local or cloud-assisted workflows.
skills: Add .NET Skills to AI Coding Agents
A curated collection of portable skills and host-specific agents for .NET and C# coding agents. It helps agents handle development, testing, upgrades, diagnostics, and other specialized .NET tasks.
DnsServer: Run a Self-Hosted DNS Server
Technitium DNS Server is a cross-platform DNS server for recursive resolution, authoritative hosting, and network-wide filtering. It suits home labs and organizations that want control over DNS, encrypted upstreams, and a browser-based management console.
Radarr: Organize and Manage Movie Downloads
Radarr manages a movie library for Usenet and BitTorrent users. It monitors feeds, works with indexers and download clients, and can import and organize downloads or upgrade existing files.
abp: Build Modular Enterprise Applications on ASP.NET Core
ABP is an opinionated .NET framework for building enterprise web applications with reusable architecture and infrastructure. It suits teams that want built-in support for modularity, multi-tenancy, and common application concerns rather than assembling each capability themselves.
KurrentDB: Store and Stream Application Events
KurrentDB is an event-native database for applications built around event sourcing and distributed messaging. It stores ordered events and provides an integrated streaming engine, with self-managed and managed-cloud deployment options.
DiscordChatExporter: Save Discord Chats to Files
DiscordChatExporter exports message history from Discord direct messages, group chats, and server channels. It suits people who need portable, offline chat archives in formats such as HTML, TXT, CSV, or JSON.