Open Source C# Libraries - Page 2
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C# Libraries
View 74 business solutionsBrowse free open source C# Libraries and projects below. Use the toggles on the left to filter open source C# Libraries by OS, license, language, programming language, and project status.
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C# Algorithms
Plug-and-play class-library project of standard data structures
A plug-and-play class-library project of standard Data Structures and Algorithms, written in C#. It contains 75+ Data Structures and Algorithms, designed as Object-Oriented isolated components. Even though this project started for educational purposes, the implemented Data Structures and Algorithms are standard, efficient, stable and tested. This is a C#.NET solution-project, and it contains three subprojects. Algorithms, a class library project which contains the Algorithms implementations. Data Structures, a class library project which contains the Data Structures implementations. Also, UnitTest, a unit-testing project for the Algorithms and Data Structures. -
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ClashN
A clash client for Windows, support Mihomo
clashN is a Windows desktop client for the Clash networking engine, providing a graphical interface to manage proxies, rules, and profiles. It wraps the Clash core in a familiar, configurable UI so users can import subscriptions, switch nodes, and observe connections without editing YAML by hand. The app emphasizes rule-based routing, letting you combine rule providers and policy groups to steer traffic by domain, process, or destination category. System-wide proxy control, including PAC and TUN/TAP options, helps route applications that don’t natively support proxies. Logs, traffic charts, and connection inspectors make troubleshooting and optimization straightforward. For power users, granular profile editing and hot-reloading reduce the friction of iterating on configurations. -
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CppSharp
Tools and libraries to glue C/C++ APIs to high-level languages
CppSharp is a tool and set of libraries that facilitates the usage of native C/C++ code with the .NET ecosystem. It consumes C/C++ header and library files and generates the necessary glue code to surface the native API as a managed API. Such an API can be used to consume an existing native library in your managed code or add managed scripting support to a native codebase. The supported target languages at present are C# and C++/CLI. It can also be used as a library to parse native code into a syntax tree with a rich declaration and type information model. Generates the glue binding code from a syntax tree of the native code. Provides APIs for parsing of C/C++ source code into a syntax tree. Mirrors the Clang's C/C++ AST and type system classes in C# APIs. -
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DockPanel Suite
The Visual Studio inspired docking library for .NET WinForms
Microsoft first introduced the docking panel layout in Visual Studio .NET (2002), and soon it became popular in application design. Many commercial .NET component vendors started to provide docking libraries initially, but there was no good free and open source alternative until WeiFen Luo released DockPanel Suite (DPS for short) on SourceForge.net in 2006. After an 18 month hiatus, the project has been resurrected and is now being actively developed on GitHub. -
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LangChain for .NET
C# implementation of LangChain
LangChain .NET is a C# implementation of the LangChain framework that enables developers to build LLM-powered applications using the .NET ecosystem. The project aims to replicate the core abstractions of LangChain, such as chains, agents, and vector stores, while adapting them to the conventions and strengths of C#. It emphasizes composability, allowing developers to build complex workflows by combining modular components that interact with language models and external data sources. The framework supports integration with multiple providers, including OpenAI and other compatible APIs, and includes tools for embeddings, document loading, and vector database interaction. It also provides both low-level async APIs and higher-level chain abstractions, giving developers flexibility in how they structure their applications. With built-in support for retrieval-augmented generation and structured pipelines, LangChain .NET is designed for production-ready AI systems. -
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LiteNetLib 1.0 indev
Lite reliable UDP library for Mono and .NET
Lite reliable UDP library for .NET Framework 3.5, Mono, .NET Core 2.0, .NET Standard 2.0. Small packet size overhead (1 byte for unreliable, 3 bytes for reliable packets). Helper classes for sending and reading messages. Always use library sources instead of precompiled DLL files (because there are platform-specific #ifdefs and workarounds for unity bugs). Fast packet serializer (Usage manual). Automatic small packets merging. Automatic fragmentation of reliable packets. Automatic MTU detection. UDP NAT hole punching. NTP time requests. Packet loss and latency simulation. IPv6 support (dual mode). Connection statisitcs (need DEBUG or STATS_ENABLED flag). Multicasting (for discovering hosts in local network). Unity support. -
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MudBlazor
Do more with Blazor, utilizing CSS and keeping Javascript to a minimum
Trusted by thousands of users, from hobby developers to large enterprises. Use MudBlazor to rapidly build amazing web applications without leaving your loved C# language and toolchain. We bring together everything that's required to build amazing Blazor applications that scale from desktop to mobile. Apart from the library itself we also provide templates, a learning platform, theme manager, demo and example projects as well as an online code editor integrated with our documentation and issue tracking. With more to come. We help companies build amazing apps in record time and let them focus on their business instead of buttons, MudBlazor is battle-tested and one of the fastest-improving platforms, and much more. We started MudBlazor with a simple promise, to empower the developer and fully take advantage of what Blazor offers. With MudBlazor you can create exceptional apps without the burden of mastering HTML, CSS and JS and focus your skillset on C#. -
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YoutubeExplode
Abstraction layer over YouTube's internal API
YoutubeExplode is a .NET library that provides a high-level abstraction for interacting with YouTube data, enabling developers to retrieve metadata and download media streams programmatically. The project exposes a clean API that allows applications to query videos, playlists, channels, and search results without relying on the official YouTube Data API. Under the hood, the library parses raw page data and leverages reverse-engineered internal endpoints to obtain structured information and stream manifests. Developers can use it to access details such as titles, authors, durations, captions, and available media formats, as well as to download audio or video streams for further processing. The library is designed to be intuitive and cross-platform through .NET Standard compatibility, making it suitable for desktop tools, automation pipelines, and media utilities. -
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eShopOnWeb
Sample ASP.NET Core 8.0 reference application
eShopOnWeb is Microsoft's .NET core sample reference application demonstrating monolithic web app architecture using Clean Architecture principles. It illustrates modern .NET patterns, organized across projects, and is designed for learning and as a starter template. The eShopOnWeb sample is related to the eShopOnContainers sample application which, in that case, focuses on a microservices/containers-based application architecture. However, eShopOnWeb is much simpler in regards to its current functionality and focuses on traditional Web Application Development with a single deployment. -
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OpenMCDF
Structured Storage .net component - pure C#
OpenMCDF is a 100% .net / C# component that allows developers to manipulate Microsoft Compound Document File Format for OLE structured storage. It supports read/write operations on streams and storages and traversal of structures tree. Development and issue tracking has moved to github platform at https://github.com/ironfede/openmcdf -
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Fast Artificial Neural Network Library is a free open source neural network library, which implements multilayer artificial neural networks in C with support for both fully connected and sparsely connected networks. Cross-platform execution in both fixed and floating point are supported. It includes a framework for easy handling of training data sets. It is easy to use, versatile, well documented, and fast. Bindings to more than 15 programming languages are available. An easy to read introduction article and a reference manual accompanies the library with examples and recommendations on how to use the library. Several graphical user interfaces are also available for the library.
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AngleSharp
The ultimate angle brackets parser library parsing HTML5, MathML, SVG
AngleSharp follows the W3C specifications and gives you the same results as state of the art browsers. Besides the official API AngleSharp adds some useful extension methods on top. This makes working with the DOM convenient. AngleSharp integrates everything you need to explore and mutate the DOM tree. Node retrieval is straight forward by using powerful CSS query selectors. The CSS queries in AngleSharp are super fast and very simple to use. AngleSharp respects the relationship of HTML with CSS. Therefore CSS is a first class citizen in the AngleSharp eco-system. Nevertheless, it is your choice if you want to use CSS with HTML, CSS alone or if you provide your own CSS solution. AngleSharp offers a lot of extension points. One of the best possibilities is providing scripting engines. This gives you a very elegant way of using JavaScript with C# on webpages. You can even script in other languages if you want to. -
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CameraVoyeur
Windows-oriented utility to log frames from a connected camera devices
CameraVoyeur is a small Windows-oriented utility that demonstrates how to capture, preview, and possibly log frames from a connected camera device in a lightweight way. It’s set up more like an experiment or proof-of-concept than a polished end-user app, focusing on the plumbing for grabbing images from the webcam. The project shows how to access the camera stream, keep it running, and expose the captured output for later use or display. Because it’s in a regular GitHub repo and not a closed binary, you can inspect the code to see how device selection, frame acquisition, and UI/display are wired. This makes it useful for developers who want to add camera capture to a Windows tool or who need a barebones sample to build surveillance, monitoring, or computer vision toys on top of. Its value is really in being a simple, readable reference rather than a big camera suite. -
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ClearScript
A library for adding scripting to .NET applications
ClearScript is a library that makes it easy to add scripting to your .NET applications. It currently supports JavaScript (via V8 and JScript) and VBScript. Simple usage; create a script engine, add your objects and/or types, run scripts. Support for several script engines: Google's V8, Microsoft's JScript and VBScript. Exposed resources require no modification, decoration, or special coding of any kind. Scripts get simple access to most of the features of exposed objects and types. Full support for generic types and methods, including C#-like type inference and explicit type arguments. Exposed .NET collections support native script iteration mechanisms. Scripts can invoke methods with output parameters, optional parameters, and parameter arrays. Support for exposing all the types defined in one or more assemblies in one step. Optional support for importing types and assemblies from script code. -
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CodeQL
Libraries and queries that power security researchers
CodeQL is a semantic code analysis engine that treats programs as queryable databases, enabling users to write expressive queries that identify security vulnerabilities, logic bugs, and code quality issues across large codebases. Instead of just pattern matching text, CodeQL ingests source code, builds rich representations of structure and data flow, and allows queries that reason about control flow, type systems, and interprocedural relationships. This makes it powerful not just for basic linting but for deep detection of complex security flaws like SQL injection, cross-site scripting, and taint propagation that traditional static analyzers can miss. CodeQL is used by security teams, developers, and open-source tooling to create reusable query libraries, enforce policy across repositories, and automate findings in CI/CD pipelines. -
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Dynamic Data
Reactive collections based on Rx.Net
Rx is extremely powerful but out of the box provides nothing to assist with managing collections. In most applications, there is a need to update the collections dynamically. Typically a collection is loaded and after the initial load, asynchronous updates are received. The original collection will need to reflect these changes. In simple scenarios the code is simple. However, typical applications are much more complicated and may apply a filter, transform the original dto and apply a sort. Even with these simple everyday operations, the complexity of the code is quickly magnified. Dynamic data has been developed to remove the tedious code of dynamically maintaining collections. It has grown to become functionally very rich with at least 60 collection-based operations which amongst other things enable filtering, sorting, grouping, joining different sources, transforms, binding, pagination, data virtualization, expiration, disposal management plus more. -
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Elsa Workflows
A .NET Standard 2.0 Workflows Library
Build workflows in code using the Workflow Builder API or as data using JSON syntax. Or use the workflow designer to design executable workflows visually. Elsa comes with a reusable dashboard component to manage workflows and activities. Run workflows from within your application using simple to use APIs. Start or resume workflows manually, or automatically by invoking triggers. Make it your own by extending the set of activities with your own. Implementing custom activities allows for powerful workflows that can be implemented with ease. Workflows can be defined using plain C# code. In addition to an increasing number of activities that you can choose from, Elsa is designed to be extensible with your own custom activities. Short-running Workflows can be useful to implement a business rules engine, while long-running workflows greatly simplify the implementation of complex processes that involve coordinating between multiple agents (users & machines). -
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LLM Tornado
The .NET library to build AI agents with 30+ built-in connectors
LLM Tornado is a provider-agnostic .NET SDK designed to build, orchestrate, and deploy AI agents and workflows with a strong focus on flexibility and integration. It provides a unified interface that connects to more than 30 AI providers and vector databases, allowing developers to switch between models and services without rewriting application logic. The framework introduces a powerful orchestration system based on graph-like structures, where agents, tasks, and transitions can be defined and executed in parallel or sequential flows. It supports multimodal inputs and outputs, including text, images, audio, and documents, making it suitable for a wide range of AI applications. LLMTornado also integrates advanced protocols such as Model Context Protocol and agent-to-agent communication, enabling complex interactions between systems. With built-in support for local deployments, enterprise guardrails, and observability features. -
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Librelancer
A re-implementation of Freelancer
Librelancer is an open-source reimplementation of the engine behind Freelancer, the iconic 2003 space trading and combat simulation game by Microsoft. Written in C# and powered by OpenGL and modern game development practices, Librelancer faithfully replicates the original gameplay while providing a flexible codebase for modding, analysis, and future enhancements. It supports original assets and is designed to be both a preservation project and a foundation for new space simulation games inspired by Freelancer’s legacy. -
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MQTTnet
High performance .NET library for MQTT based communication
MQTTnet is a high-performance .NET library for MQTT-based communication. It provides an MQTT client and an MQTT server (broker) and supports the MQTT protocol up to version 5. TLS support for client and server (but not UWP servers). Extensible communication channels (e.g. In-Memory, TCP, TCP+TLS, WS). Lightweight (only the low-level implementation of MQTT, no overhead). Performance optimized (processing ~150.000 messages/second). Uniform API across all supported versions of the MQTT protocol. Tested on the local machine (Intel i7 8700K) with MQTTnet client and server running in the same process using the TCP channel. The app for verification is part of this repository and stored in /Tests/MQTTnet.TestApp.NetCore. List of connected clients available. Supports connected clients with different protocol versions at the same time. Able to publish its own messages (no loopback client required). Able to receive every message (no loopback client required). -
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NetTopologySuite
A .NET GIS solution that is fast and reliable for the .NET platform.
A .NET GIS solution that is fast and reliable for the .NET platform. NetTopologySuite is a direct port of all the functionalities offered by JTS Topology Suite: NTS exposes JTS in a '.NET way', for example using Properties, Indexers, etc. The JTS Topology Suite is an API for modeling and manipulating 2-dimensional linear geometry. It provides numerous geometric predicates and functions. JTS conforms to the Simple Features Specification for SQL published by the Open GIS Consortium. -
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QuestPDF
A library that can help you with generating PDF documents
Quickly design and generate PDF documents with an open-source, modern, and battle-tested C# library. Forget about limitations, feel confident, enjoy your task and efficiently deliver professional products. QuestPDF is a progressive library that can help you with generating PDF documents in your .NET application by offering a friendly, discoverable and predictable C# fluent API. Do you believe that creating a complete invoice document can take less than 200 lines of code? We have prepared for you a step-by-step instruction that shows every detail of this implementation and describes the best patterns and practices. This library is created specifically for designing and arranging document layouts, with full paging support. Alternative solutions, such as HTML-based converters, are not designed for this purpose and therefore are often unpredictable and do not produce desired results. -
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Spectre.Console
Library that makes it easier to create beautiful console applications
Spectre.Console is a .NET library that enables the creation of rich, cross‑platform console applications. Heavily inspired by Python’s Rich library, it provides advanced styling, layout, and input capabilities for modern terminal UIs. Supports tables, grids, panels, and a Rich inspired markup language. Supports the most common SRG parameters when it comes to text styling such as bold, dim, italic, underline, strikethrough, and blinking text. Supports 3/4/8/24-bit colors in the terminal. The library will detect the capabilities of the current terminal and downgrade colors as needed. Written with unit testing in mind. -
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Stripe.net
Stripe.net is a sync/async .NET 4.6.1+ client
A .NET library to facilitate Stripe payment integration, supporting a full range of payment and subscription features for .NET applications. -
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Windows UI Library
Windows 10 native controls and Fluent styles for your applications
WinUI is a user interface layer that contains modern controls and styles for building Windows apps. As the native UI layer in Windows it embodies Fluent Design, giving each Windows app the polished feel that customers expect. WinUI 2 is a library of controls that provides official native Microsoft UI controls and features for Windows UWP apps. WinUI 2 can be used in any Windows 10 UWP XAML app, or in a Xamarin.Forms app running on Windows 10 using native view embedding. WinUI 3 is the next generation of the WinUI framework. It dramatically expands WinUI into a full UX framework, making WinUI available for all types of Windows apps, from Win32 to UWP, for use as the UI layer. You can build new Windows apps using WinUI 3, which ships as a part of the Windows App SDK. The latest available stable release is the Windows App SDK 0.8 (previously called Project Reunion). With this release, you can ship production Desktop apps to the Microsoft Store.
