Slack is not available as a self-hosted solution but there are plenty of alternatives for power users and business that want to host a solution on-premise. The best open source Self-Hosted alternative is Zulip. It's not free, so if you're looking for a free alternative, you could try Zulip or Element. If that doesn't suit you, our users have ranked more than 100 alternatives to Slack and many of them are open source and available as a self-hosted solution so hopefully you can find a suitable replacement. Other interesting open source Self-Hosted alternatives to Slack are Wire, Rocket.Chat, Armada and Buzz.
Threaded group conversations combine live and asynchronous messaging, separating topics for organized collaboration, supporting open-source, cloud, and self-hosted deployments, secure communication with encryption, and multi-platform access for diverse teams.
United States
Provides secure collaboration with end-to-end encryption, supporting chat, voice, and video calls. Available on all major platforms, it enables digital sovereignty with a decentralized design and interoperability through bridges to systems like Slack and Teams. Includes enterprise-grade SaaS.
United Kingdom
Open standard protocol enabling decentralized, encrypted instant messaging, VoIP signaling, IoT device connectivity, and persistent data management across federated servers without central control or single points of failure, bridging communication platforms.
United Kingdom
Secure communication platform featuring encrypted chats and calls, file and media sharing, self-deleting messages, device verification, group collaboration, and customizable settings. Supports use across multiple devices with no phone number required for access.
Switzerland
Open-source chat server supporting real-time group, direct, and private messaging, video calls, file sharing, helpdesk chat, API integrations, desktop notifications, emojis, LDAP authentication, cross-platform apps, and customizable extensions for teams.
United States
Open-source, end-to-end encrypted chat supporting decentralized, serverless communities and Concord. Features self-hosting, cryptographic login, encrypted text channels, threads, live voice and video rooms, compatibility with Nostr and other protocols, custom emojis, and GIFs.
United States
United States
Decentralized social and blog platform based on XMPP, enabling self-hosting, cross-network chat, video calls, and group collaboration. Users control and migrate their data, communicate across various networks, and access services from any node while preserving privacy and open-source principles.
France
EU
Twake is a real-time teamwork platform. It is a suite of collaborative tools that includes the specificities of some bestsellers (Slack, Trello, Google Drive...). We provide professional messaging, storage space, online collaborative editors (Words, Excel, PowerPoint), task...
FranceEU
Self-hosted communication platform with secure audio, video, chat, web conferencing, screensharing, advanced encryption, and metadata privacy, running on user-controlled servers, supporting web and mobile apps, and eliminating third-party data exposure.
GermanyEU
Decentralized chat platform built on the nostr protocol with support for multi-group communities, event calendars, threads, private messaging, web of trust, customizable access controls, monetization via zaps, full privacy, and white-label options for branding.
United States
Powered by WebRTC, Real-time video call, chat room and screen sharing entirely browser based.
ItalyEU
