Free .NET libraries

I have used a lot of free .NET libraries, some from Microsoft itself! Which ones have you found the most useful?

Package managers for external libraries

  • NuGet (formerly known as NuPack) – Microsoft (developer-focused package management system for the .NET platform intent on simplifying the process of incorporating third party libraries into a .NET application during development)
  • OpenWrap – Sebastien Lambla – Open Source Dependency Manager for .net applications

Build Tools

  • Prebuild – Generate project files for all VS version, including major IDE’s and tools like SharpDevelop, MonoDevelop, NAnt and Autotools

Dependency Injection/Inversion of Control



Design by Contract




 Data Mapper



PDF Creators/Generators

Unit Testing/Mocking

Automated Web Testing

Misc Testing/Quality Support/Behavior Driven Development (BDD)

URL Rewriting

Web Debugging

  • Glimpse – Firebug for your webserver


MS Word/Excel Documents Manipulation

  • DocX to create, read, manipulate formatted word documents. Easy syntax, working nicely, actively developed. No Microsoft Office necessary.
  • Excel XML Writer allows creation of .XLS (Excel) files. No Microsoft Office necessary. Been a while since it has been updated. It also provides code generator to create code from already created XLS file (saved as xml). Haven’t tested this but looks very promising. Too bad author is long time gone.
  • Excel Reader allows creation/reading of .XLS (Excel) files. No Microsoft Office necessary. Been a while since it has been updated.
  • Excel Package allows creation/reading of .XLSX (Excel 2007) files. No Microsoft Office necessary. Author is gone so it’s out of date.
  • EPPlus is based on Excel Package and allows creation/reading of .XLSX (Excel 2007). It is actually the most advanced even comparing to NPOI.
  • NPOI is the .NET version of POI Java project at POI is an open source project which can help you read/write xls, doc, ppt files.

Social Media

  • LinqToTwitter – Linq-based wrapper for all Twitter API functionality in C#
  • Facebook C# SDK – A toolkit for creating facebook applications / integrating websites with Facebook using the new Graph API or the old rest API.


  • sharpserializer – xml/binary serializer for wpf, and silverlight
  • protobuf-net – .NET implementation of google’s cross-platform binary serializer (for all .NET platforms)

Machine learning

  • Encog C# – Neural networks
  • – AI, computer vision, genetic algorithms, machine learning


  • CSLA Framework – Business Objects Framework
  • Prism – Composit UI application block for WPF, Silverlight and WP7 – Microsoft patterns & practices
  • Enterprise Library 5.0 – Logging, Exception Management, Caching, Cryptography, Data Access, Validation, Security, Policy Injection – Microsoft patterns & practices
  • File helpers library
  • C5 Collections – Collections for .NET
  • Quartz.NET – Enterprise Job Scheduler for .NET Platform
  • MiscUtil – Utilities by Jon Skeet
  • Noda Time – DateTime replacement (idomatic port of Joda Time from Java)
  • – Text indexing and searching
  • Json.NET – Linq over JSON
  • Flee – expression evaluator
  • PostSharp – AOP
  • IKVM – brings the extensive world of Java libraries to .NET.
  • C# Webserver – Embeddable webserver
  • Long Path – Microsoft
  • .NET Engines for the GOLD Parsing System
  • Smart Thread Pool – Thread Pool management library
  • NCQRS – library for event-driven architectures (CQRS).
  • NBug – Automated exception, error reporting tool (can generate minidumps)
  • Math.NET Numerics – special functions, linear algebra, probability models, random numbers, interpolation, integral transforms and more
  • Splicer.Net – library for the .Net framework that aims to simplify developing applications for editing and encoding audio and video using DirectShow.
  • – Lightweight RouteHandler for ASP.NET MVC that will generate automatic jQuery based Javascript.

Please provide links to these free libraries as well. Once we have a huge list of this, it can be arranged in categories! Please do not mention .NET Applications/EXEs here. Please write comments…

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8 Responses to Free .NET libraries

  1. Vincenzo says:

    Please consider to add JsAction too!

  2. Hema says:

    Thank you so much for sharing valuable .net liberies in a single article!!!.

  3. Waegner says:

    this short article really helps to me,thank ough.

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