Open-source alternatives to Chat

Centrifugo is a self-hosted real-time messaging server that provides infrastructure for scalable notifications, a publish-subscribe message broker, and a language-agnostic WebSocket gateway. It allows for the delivery of instant messages and data streams to concurrent users via WebSockets and Server-Sent Events. The system functions as a communication layer that separates network transport from backend business logic. It supports distributed messaging clusters using Redis for coordination of presence and message delivery across multiple server nodes. The project covers channel subscription m

InsForge is a backend-as-a-service platform that provides an integrated suite of tools for managing relational databases, identity provision, object storage, and serverless compute. It functions as an open-source identity provider and a PostgreSQL database manager featuring integrated vector storage and row-level security. The platform serves as an LLM orchestration gateway, offering a unified endpoint to route requests across various AI providers through an OpenAI-compatible interface. It enables AI-driven application generation and connects AI agents to backend resources using a standardize

Parse Server is a backend-as-a-service solution and Node.js framework that provides a ready-to-use REST and GraphQL API for mobile and web applications. It functions as a core backend infrastructure for managing database schemas, user authentication, and API routing. The system distinguishes itself with a real-time data engine that pushes database updates to clients via WebSockets and a GraphQL server that automatically generates schemas based on application data models. It also features an adapter-based storage layer that abstracts interactions with various cloud and local backends. The pla

HuLa is an open-source communication suite and cross-platform chat client designed for real-time instant messaging, voice, and video calls. It functions as an LLM-integrated messaging platform and an AI-powered social manager that synchronizes user data and settings across different operating systems. The platform integrates large language models to provide automated AI assistants, real-time message translation, and chat log summarization. It further utilizes artificial intelligence for user sentiment analysis to assist with social matching and risk management. The system includes a high-per

SpaceBarChat is an open-source, self-hosted chat server that implements the Discord client-server protocol, allowing existing Discord clients and bots to connect without modification. It provides a complete communication platform for real-time messaging, voice, and video, all running on your own infrastructure with data stored in a PostgreSQL database that automatically synchronizes its schema with the application source code. The platform is built on a three-service architecture that separates API, Gateway, and CDN processes, communicating via Unix domain sockets or RabbitMQ for coordination

This project is a comprehensive sample library and implementation guide for ASP.NET Core. It provides a collection of practical examples and projects that demonstrate how to build web applications, RESTful APIs, and high-performance services. The repository focuses on a variety of architectural patterns, including the development of Minimal APIs, contract-first gRPC services, and real-time communication using WebSockets and Server-Sent Events. It includes detailed implementations for user identity and security, such as token-based authentication and CSRF protection. The codebase covers a bro

Telebot is a framework for building interactive bots using the Telegram Bot API. It provides a type-safe API wrapper and an asynchronous event handler to manage messages, commands, and user interactions. The project features a middleware-based request interception system and pattern-based event routing to map triggers to custom logic. It includes a dedicated inline query engine for generating real-time suggested results and an interactive keyboard builder for creating custom reply and inline buttons. The framework covers a broad range of capabilities, including rich media management for albu

Lets-chat is a self-hosted team communication platform and XMPP chat server designed for private messaging. It provides a containerized communication environment for small teams to exchange messages and files, featuring a programmable REST API for automating conversations and managing messages from external tools. The platform functions as an XMPP gateway and server, ensuring interoperability with other compliant messaging clients. It distinguishes itself by supporting enterprise identity management, allowing administrators to verify user identities through local accounts or external director

Realtime is a real-time data distribution and synchronization engine that enables applications to stream database changes and coordinate state between clients. It functions as a synchronization layer that monitors database write-ahead logs to provide change data capture and pushes updates to authorized clients via WebSockets. The project features a real-time presence server for tracking the online status of active users and a broadcast service for sending ephemeral messages without database persistence. It organizes communication through channel-based message routing and uses a structured JSO

Mattermost Server is an open source collaboration suite and self-hosted team communication platform. It functions as an enterprise chat server and extensible messaging backend that provides a secure environment for professional organizations to exchange messages and coordinate software development. The platform is designed as an AI-integrated communication hub, embedding artificial intelligence into messaging flows to assist users with information retrieval and task completion. It supports a high degree of customization through a plugin-based extension model, allowing for the creation of cust

Baileys is a TypeScript API client library used to interact with the WhatsApp Web API via WebSockets without requiring a browser. It functions as a real-time communication tool that handles bidirectional data exchange and event-based socket connections. The project includes a dedicated toolkit for managing WhatsApp Business profiles and product catalogs, alongside a session manager that authenticates accounts using QR codes or pairing codes and persists session state to disk. Its capabilities cover a wide range of messaging functions, including multi-type message transmission, chat history s

Janus is a WebRTC media gateway that routes real-time audio, video, and data between web browsers and server-side application logic. It functions as a central media relay that manages session negotiation and encryption for multiple browser endpoints. The project utilizes a modular plugin architecture that decouples the core server from specific media logic, allowing developers to implement custom modules for media processing, event handling, and transport protocols. This design enables the server to act as a protocol translation bridge, converting WebRTC streams into legacy formats such as SI

Once Campfire is a self-hosted team chat platform and real-time messaging server. It provides a web-based communication environment for internal team messaging, featuring group channels, private direct messages, and a bot-integrated system for automating external messaging services. The platform is distributed as a dockerized collaboration suite, allowing for containerized deployment with bundled application dependencies and automated SSL provisioning. The system covers a broad range of collaboration capabilities, including chat management with granular access controls, file attachment shari

This project is a comprehensive technical interview preparation resource and computer science interview guide. It serves as an educational reference for developers to study core software engineering fundamentals and common coding patterns required for employment screenings. The repository provides detailed guides and references covering data structures and algorithms, networking and security, operating systems, and web development. It specifically focuses on the implementation and complexity analysis of sorting, searching, and graph algorithms. The material encompasses a wide breadth of comp

Pangolin is a zero-trust remote access platform designed to provide secure, identity-aware connectivity to private network resources. It functions as a cloud-native network controller that orchestrates encrypted tunnels, traffic routing, and access policies across distributed environments. By leveraging WireGuard for secure data transport, the platform enables authenticated access to internal web applications, terminal sessions, and remote desktops without exposing services to the public internet. The platform distinguishes itself through a declarative infrastructure model that synchronizes n

Flamingo is a self-hosted instant messaging platform and collaborative communication suite. It provides a centralized backend for user authentication and message routing, enabling real-time text and multimedia exchange for distributed teams. The platform integrates a remote desktop tool for administering sessions directly within the communication flow and utilizes a store-and-forward system to ensure files and messages are delivered to offline users. It also includes an automated client update system that detects and installs software updates across supported desktop operating systems. The s

This project is a self-hosted communication suite and private messaging infrastructure. It is a containerized chat platform designed for deployment on independent hardware to maintain full control over user data and server dependencies. The system features a modular plugin framework that allows custom features and behaviors to be loaded into the client at runtime via manifest files. It is designed as a proxy-compatible service, supporting configurable network port routing to operate behind external reverse proxy servers. The platform covers capabilities for containerized service orchestratio

This project is an instant messaging application and social networking platform. It provides a system for exchanging text, media files, and real-time voice or video calls, while maintaining a digital space for users to manage friend lists and interact within social circles. The platform integrates digital payment systems for financial transactions and monetary gifting, such as red envelopes, within the chat interface. It also includes a mobile business office framework designed to link online interactions with physical service delivery and professional business operations. Capabilities cover

Mumble is a low-latency voice over IP system designed for real-time communication. It provides a self-hosted, encrypted voice server that secures data transmission using public-private key authentication and digital certificates. The platform distinguishes itself through a request-response protocol for remote configuration and integration with external automation scripts. It also features a graphical overlay that renders active speaker information and chat status on top of other running applications, as well as positional audio to simulate the 3D spatial location of speakers in a virtual envi

Jetstream is an application scaffold for Laravel that provides a pre-built identity system and team collaboration framework. It serves as a starter kit that integrates user authentication, profile management, and organizational tools into a unified project structure. The project is distinguished by its comprehensive team management capabilities, which include shared workspace organization, member invitation workflows, and role-based access control. It also features an integrated API token manager for issuing and controlling secure access tokens for external clients. The platform covers a bro

This repository is a collection of Java backend projects, encompassing a web application suite, a real-time chat server, a web crawler, and an authentication system. It provides implementations for building server-side logic and business rules to process data and handle web requests. The project includes a networked messaging system for instant bidirectional communication and an automated web scraping engine that parses HTML to aggregate data into local storage. It also features a security framework for managing user permissions and generating visual captchas to prevent automated bot access.

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This project is a comprehensive course on building server-side applications using the Node.js runtime and Express web framework. It provides instructional material for developing REST APIs, managing backend development, and creating web servers. The curriculum includes specialized guides for implementing user authentication systems, such as email verification and password reset flows, and a dedicated lab for integrating Stripe to handle recurring subscription billing and financial transactions. The course covers broad capability areas including MongoDB database integration for data storage,

Legendary is a game management tool designed for downloading, installing, and updating game files from remote servers without the use of official store clients. It provides a means to list available account titles, track installed games, and import existing local installations by verifying files. The project enables the management of Steam game libraries on systems where the official client is unsupported and supports the activation of titles from third-party accounts through external authorization systems. It also provides tools for configuring Linux gaming environments, specifically through

This backend starter template provides a modular structure for building REST APIs using Node.js, Express, and MongoDB. It includes predefined database models, schema-driven validation, and structured routing to facilitate the development of server-side applications. The application incorporates authentication and security features centered on user registration, login flows, and credential verification. Passwords are protected using cryptographic hashing, and access to protected endpoints is managed through signed token issuance and middleware-based route protection. Additional identity manage

Discordo is a command-line interface client for Discord that enables terminal-based communication. It allows users to access servers and send messages through a keyboard-driven text interface instead of a web browser or desktop application. The client features a customizable interface where users can modify themes, keybindings, and general settings via a flat-file configuration system. Identity verification is handled through user account authentication using either authentication tokens or a QR-code scanning flow. These mechanisms establish secure sessions to communicate with the Discord AP

PartyKit is a serverless WebSocket backend platform for building real-time multiplayer applications. It provides a globally distributed edge computing runtime that runs stateful server code close to users, with automatic scaling and hibernation for idle rooms. The platform handles WebSocket connections, HTTP requests, and durable storage without requiring infrastructure management, and includes a client and server SDK with hooks, storage, and Yjs integration for building collaborative features. The platform distinguishes itself through per-room isolation using Durable Objects, where each uniq