Open Source C# Chat Software

See https://pidgin.im/about/ for more information. Pidgin is an instant messaging program which lets you log in to accounts on multiple chat networks simultaneously. It runs on Windows, Linux, and other UNIX operating systems. Pidgin is compatible with the following chat networks out of the box: AIM, ICQ, Google Talk, Jabber/XMPP, MSN Messenger, Yahoo!, Bonjour, Gadu-Gadu, IRC, MXit, Novell GroupWise Messenger, Lotus Sametime, SILC, SIMPLE, MySpaceIM, and Zephyr. It is written in C and makes heavy use of GLib and GTK+. Finch is a command line instant messaging program. It also lets you log in to accounts on multiple chat network simultaneously, and it is compatible with the same chat networks as Pidgin. It is written in C and makes heavy use of GLib and ncurses.

DiscordChatExporter is a cross-platform utility that allows users to export Discord chat histories into structured files for archival, analysis, or backup purposes. The tool connects to Discord accounts and retrieves message history from servers, channels, or direct messages, then converts the data into formats such as HTML or JSON. It is designed to preserve message structure, timestamps, attachments, and formatting so exported conversations remain easy to navigate and review. The project is widely used for moderation audits, research, community archiving, and personal record keeping. With both command-line and GUI usage patterns available through the ecosystem, it supports automation as well as manual workflows. Overall, DiscordChatExporter provides a reliable way to extract and preserve Discord communications outside the platform.

HunterPie is a modern overlay application for Monster Hunter games that gives players real-time information during hunts. It was rewritten from scratch for its v2 generation while keeping the same focus on a clean, powerful, and easy-to-use experience. The overlay can show hunting data through modules, plugins, widgets, and customizable interface elements. It is useful for players who want clearer visibility into damage, monster data, party performance, and other hunt-related context. The project is built as a desktop application and requires the .NET Desktop Runtime. HunterPie is best understood as an extensible companion tool for Monster Hunter players who want more feedback and personalization than the base game interface provides.

RevokeMsgPatcher is a reverse engineering patch tool for Chinese messaging apps QQ and TIM. It prevents message recall (revocation) by modifying the app’s behavior to retain recalled messages, allowing users to see messages that would otherwise be deleted. Primarily used in Windows environments, the tool is popular among users who prefer transparency in their chats.

ThinLisp is a practical dialect of lisp for real world applications. You develop in Common Lisp, you deploy in C. ThinLisp programs are as fast as C, by design. Used for a decade in million line systems.

Yammy (Yahoo Messenger Archive Decoder) allows you to decode and view not only yours but, also other stored YM conversations. You don't even need a password!

Driver support for 3D Controller Hardware. We hope to support SDL Input, DirectInput, and other major controller API's including game consoles and embedded systems.

YaP is an IRC Client written in C#.

DotChat is a client/server chat application which allows any number of users on a network to conduct multiple conversations with other network members.

A. R. Live Support is online chat software, developed in Asp.net(2.0) and XML. Easy to use and it facilitates 1-o-1 live communication between customers and executives. Flexible live chat software that provides the customer support with a click.

nebohodimo IM is a Jabber client for Windows Mobile devices. It's written to be stable over unreliable mobile connection and easy to use.

A light-weight yet feature-rich Second Life chat client.

#aim (pronounced "shame") is a multi-protocol instant messaging client written in C#

.IRC (or dotIRC) is an IRC client written in C#. Its goal is to provide an easy to use IRC client that will be eventually be compatible with Microsoft's System.Windows.Forms library under .NET and GTK# under Mono. It is using the SmartIrc4net library.

This is a set of .NET class libraries, designed to use various Internet protocols in a easy-to-use OO matter. So far it contains a POP3 and an IRC (Internet Relay Chat) library.

.nIRC is an IRC client written in C#. It has full support for text formatting, file sending, etc, and allows the use of IronPython scripts in order to make further customisation easier.

A c# implementation of the achat protocol. It is a seperate library so you can add your own interface. there are also two pre-made implementations. one basic (and incomplete) GUI version and a just as useful console version

AIML Verbot Converter - Converts AIML files to Verbot KnowledgeBase (VKB) files. Visit http://www.verbots.com/ and http://www.alicebot.org to learn more about AIML and Verbots. Implemented in C# (.NET).

THIS LIBRARY IS NOT UNDER ACTIVE DEVELOPMENT (sorry). AIMLBot (Program#) is a small, fast, standards-compliant yet easily customizable .NET dll implementation of an AIML (Artificial Intelligence Markup Language) based chatter bot. AIMLBot has been tested on both Microsoft's runtime environment and Mono.

This is another Age of Conan chat bot written in C#. Support for loading and unloading plugins while running through AppDomain. Uses a fairly easy way of implementing new plugins through the Abot.Plugin class. Using Vhab's VhaBot.Net library.

JavaScript Chat based on DOM and AJAX technologies. Content refreshing without roundtrip of page.

Aeru IRC is IRC Client for the .NET Framework. It made with C# programming language and features a full Graphical Interface. Aeru IRC uses XML to store servers and channels and app settings. The GUI uses the power of .NET.

A simple an easy to use Instant Messenger application to use on networked computers. Minimal to no setup required.

AlterEego intends to re-create the popular server system, Second Life. Base code from OpenSim, used under BSD License.