Open Source Alternatives to Slack
A collaboration and communication platform that enables teams to chat, share files, run huddles, and integrate AI agents, providing searchable conversation history and workflow automation.
Whether you want to cut software costs or escape vendor lock-in, these open source alternatives to Slack give you an option you fully own. Run them on your own server or desktop, so your data stays under your control. This page lists 20 open source alternatives to Slack. The most popular are Rocket.Chat, Mattermost and Huly. Most use the Apache-2.0 or AGPL-3.0 license, and 15 offer an official Docker image.
Rocket.Chat
A secure communication platform providing real-time messaging, voice, and video for organizations requiring full data control.
Mattermost
A self-hosted collaboration platform providing team chat, workflow automation, voice calling, and screen sharing for secure organizations.
Huly
Integrates project management, team chat, CRM, and collaborative documents into a single self-hosted business application framework.
Zulip
An organized team chat application using topic based threading to support both live and asynchronous communication.
Element
A communication client for encrypted messaging and collaboration built on the decentralized Matrix protocol.
HuLa
A cross-platform instant messaging system providing private and group chat capabilities across desktop and mobile devices.
Colanode
A local-first collaboration workspace combining real-time chat, rich text pages, databases, and file management for teams.
Synapse
A homeserver implementation for the Matrix open standard for secure and interoperable real-time communications.
Campfire
A self-hosted group chat system featuring multiple rooms, direct messaging, file attachments, and bot integration via API.
Cinny
A secure and modern Matrix client providing an encrypted interface for decentralized instant messaging conversations.
Converse
A client side XMPP chat application that runs in web browsers or as a desktop app.
Openfire
A real time collaboration server using the XMPP open protocol for instant messaging and communication.
Quiet
A peer-to-peer team chat that syncs messages directly between devices over Tor without central servers.
Stoat
A self-hosted communication platform featuring a back-end, web front-end, file server, and image proxy.
Wire
Provides end to end encrypted messaging, file sharing, and video calls for secure team communication and collaboration.
nheko
A native desktop client for the Matrix protocol designed to feel like a mainstream chat application.
Mattermost
Provides a native desktop interface for secure team collaboration and communication across Windows, Mac, and Linux.
MongooseIM
An XMPP server designed for large installations that supports clustering and multiple client connection methods.
Mezon
A communication platform for communities and teams featuring encrypted messaging, voice calls, and AI moderation tools.
ngIRCd
A portable and lightweight Internet Relay Chat server designed for small or private networks.
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