Open Source Objective C Messaging Platforms

Adium is an Open Source, multi-protocol instant messaging application for Mac OS X. Adium supports AIM, ICQ, Jabber, MSN, Yahoo!, Google Talk, Bonjour, Gadu-Gadu, Novell Groupwise, SIP/SIMPLE (Text), and Lotus Sametime. Additionally, it supports all of these applications at once so, even if you have multiple IM accounts, you don't have to log into each account separately.

Instant messenger client for GNUstep. Using Björn Giesler's port of the AddressBook framework, Angelos accesses the user's addressbook to produce a buddylist with real names and photos.

Azonto is a Cross-Platform Mobile Messaging Application that allows users to share images, songs, videos, create and add each other to groups. It is for the trendy who wants to be on top of the mobile messaging game.

Chat Messaging App Light and Dark Theme is a Flutter UI project for building a messaging app interface with both light and dark modes. It includes multiple screens that cover the core visual flow of a chat application, starting with a welcome screen and moving into authentication and conversation views. The project is intended as a design and implementation reference rather than a complete messaging backend. It demonstrates how Flutter layouts can be structured for chat lists, message screens, onboarding, sign-in, and sign-up experiences. The dual theme support makes it useful for learning how to design consistent interfaces across different visual modes. It is best suited for Flutter learners and mobile developers who need a clean UI base for chat-style apps.

Fire is a multi-protocol instant messenger client for Mac OS X based on freely available libraries for each service. Currently Fire handles AOL Instant Messenger®, ICQ®, MSN® Messenger, Jabber, limited IRC, Yahoo!®, and Apple Bonjour communications.

MobileIMSDK is a lightweight cross-platform instant messaging communication framework designed for real-time chat and push-style communication. It supports multiple client platforms, including iOS, Android, Java, HTML5, mini programs, UniApp, and HarmonyOS Next, with a Netty-based server side. The framework is notable for supporting UDP, TCP, and WebSocket protocols in the same open-source IM communication layer. It has been developed and refined over many years, making it a mature option for teams building custom messaging systems. MobileIMSDK focuses on the communication layer rather than a complete consumer chat app, so developers can build their own user interface and business logic on top of it. It is useful for mobile apps, web apps, enterprise messaging, live communication features, and custom push systems.

WeChatExtension-ForMac is an unofficial plugin that enhances the WeChat desktop experience on macOS by adding new features such as message anti-recall, multi-instance login, auto-reply, and UI customization. Designed for users who want more control and functionality from their desktop WeChat client, this plugin requires patching the app and may violate WeChat’s terms of service.

WeChatPlugin-MacOS is an unofficial plugin for the macOS version of WeChat, providing features like auto-reply, message anti-recall, and remote control. It injects custom functionality into the official WeChat client using macOS’s dynamic library loading, offering power-user features not present in the native app. This project has been widely used but is no longer actively maintained due to security and compatibility concerns.