Best open-source alternatives to Discord

Discourse is an open-source community platform designed for people who want to host their own discussion spaces with full control over infrastructure and configuration. It is positioned as a forum and community hub, with official hosted service available for teams that prefer not to manage servers themselves. The platform supports core community features such as discussion topics, real-time chat, themes, and plugins, making it suitable for public forums, support communities, and other collaborative spaces. The README also highlights a long-running ecosystem, documentation for development and setup, and a RESTful Rails-backed API, indicating a mature web application built for extensibility and self-hosting.

Rocket.Chat is an open-source communications platform aimed at organizations that need secure, customizable collaboration tools. It supports team messaging and real-time conversations for internal coworkers as well as external communication with customers, citizens, or partner companies. The project is designed for self-hosted, cloud, and air-gapped deployments, making it suitable for regulated or high-security environments. It also includes security and governance features such as identity management, end-to-end encryption, and role- and attribute-based access control, while offering extensibility through a marketplace, Apps-Engine, and external integrations.

Mattermost is an open core collaboration platform designed for teams that want to self-host their communication and workflow stack. It provides a web-based interface and native clients for desktop and mobile, and is positioned for use cases such as DevSecOps, incident resolution, and IT service desk operations. The project is the primary source for core platform development and is implemented in Go and React. The software runs as a single Linux binary and depends on PostgreSQL for storage. The README emphasizes deployment flexibility, with installation paths for Docker, Ubuntu, tar archives, Kubernetes, and Helm. It also points users to product and developer documentation, and highlights a broad integration surface including webhooks, slash commands, drivers, web services, apps, and plugins.

Zulip is an open-source team chat platform designed to help organizations manage both real-time and asynchronous communication in a more structured way than traditional chat apps. Its signature feature is topic-based threading, which keeps conversations organized and makes it easier for distributed teams to follow multiple discussions without losing context. The project is aimed at teams, open-source communities, and other organizations that need productive group communication. The README highlights self-hosting on Ubuntu or Debian Linux, deployment via Docker, and hosted cloud options through Zulip Cloud. It also emphasizes a large contributor community and extensive documentation for both code and non-code contributions, suggesting a mature project with a broad user and developer ecosystem.

Element is a Matrix client aimed at people who want to access Matrix chats through either a web browser or a desktop application. The README positions it as the main Element Web project in a larger monorepo, with related components and documentation links for installation, configuration, development, and translation. It can be used immediately through the hosted service at app.element.io, or self-hosted by following the installation documentation. The project also supports a desktop experience through an Electron wrapper, with pre-built downloads available from Element’s site or a path to build it from source. The README emphasizes browser compatibility, community triage, and a commercial licensing option alongside open-source licensing.

Mumble is an open source voice-chat system built on Qt and Opus. It is aimed at users who need real-time, low-latency communication, and it is split into a desktop client and a separate server component. The client is available on Windows, Linux, FreeBSD, OpenBSD, and macOS, while the server can run wherever Qt is available. The project appears to serve both individual users and communities that want to host their own voice infrastructure. The README points to build instructions, server configuration documentation, and plugin documentation, suggesting it is suitable for self-hosted deployments and for extending functionality through plugins. It also includes an OpenGL overlay feature for games and references packaged, Docker-based, and source-build installation paths.

The Lounge is a self-hosted web IRC client intended for people who want a persistent, browser-based way to stay connected to IRC networks. It is positioned as a modern alternative to traditional IRC clients, with features such as push notifications, link previews, and message markers to make IRC feel more contemporary. It is aimed at users who want their IRC presence to persist across devices and sessions. The README emphasizes that it stays connected while the user is offline, works across platforms wherever Node.js runs, and provides a responsive interface for desktop, smartphone, and tablet use. The project also documents a source-based installation path for development and links to a Docker-based deployment option for stable releases.

Synapse is a Matrix homeserver implementation developed and maintained by Element. It is intended for people and organizations that want to run their own Matrix server for secure, interoperable real-time communication, either from source or as part of Element’s deployment offerings. The README emphasizes that Synapse can be deployed standalone, with documentation covering installation, configuration, federation, reverse proxy setups, and upgrades. It is also shipped as part of Element Server Suite, which provides official deployment paths and commercial support options. The project is open source under AGPL, with an additional commercial license available from Element for organizations that need that arrangement.

Campfire is a web-based chat application designed for teams or groups that need a self-hosted messaging system. It provides familiar collaboration features such as rooms, direct messages, file attachments, search, mentions, and push notifications, along with access controls for rooms. The project is positioned as a single-machine deployment that bundles the web application, background jobs, caching, file serving, and SSL into one Docker image. The README also indicates that Campfire is intended to be administered locally by the operator, who creates an initial admin account on first launch. It is single-tenant, meaning separate customer groups would require separate instances rather than isolated workspaces within one deployment. The included API support suggests it can be extended for bot integrations and other external automation.

Tailchat is an open source instant messaging and collaboration platform positioned as a “noIM” application: it aims to go beyond chat and act as a customizable workspace for individuals, teams, and enterprises. The project emphasizes privacy, invited-only groups, and a structure that lets users organize discussions into panels and spaces rather than relying on a traditional flat chat model. It is built with a front-end microkernel and a backend microservice architecture, and its plugin system is meant to let developers extend the product and integrate third-party applications in a native-feeling way. The README presents Tailchat as suitable for scalable deployments and secondary development, with official documentation, a nightly online demo, and deploy options referenced for container-based hosting.