Slack is where a lot of company knowledge lives: decisions, context, the thread someone needs six months later. Moving it is not a small decision, and the case for moving it is usually about data control — who can read your internal communication, and under whose jurisdiction the servers sit.
This post is part of a series on moving off American software. It walks through the European team chat options listed on European Alternatives, grouped by what kind of organization they suit. There is no single best one; there is a best fit for how your team actually works.
End-to-end encrypted messengers
If confidentiality is the primary requirement, start here.
Threema Work is a business messaging service from Switzerland, built for companies and public authorities that need confidential internal and external communication. It offers end-to-end encrypted text and voice messages, group chats, video calls and file sharing, with centralized user and license management through a web-based management cockpit. Apps exist for iOS, Android, Windows, macOS and Linux, and a self-hosted variant called Threema OnPrem exists for organizations that need full infrastructure control. Note that Threema Work is a distinct subscription product from the company's consumer messenger, Threema Private.
Wire, also from Switzerland, covers iOS, Android, Windows, macOS and Linux. Communication is end-to-end encrypted and the apps are open source.
ginlo Business comes from a German company that also runs a consumer messenger, ginlo Private.
Open source you can self-host
Element is an open source team communication app from the United Kingdom, built on the open Matrix protocol. Instead of routing every conversation through one company's servers, Element connects to independent Matrix homeservers — your own, or the public matrix.org server that Element operates on behalf of the nonprofit Matrix.org Foundation. All conversations are end-to-end encrypted, and devices must be verified before they can send or receive encrypted messages. Apps cover web, desktop, iOS and Android, and existing Slack, Microsoft Teams or IRC channels can be bridged into Matrix rooms. It is used by companies, public administrations and individuals who want communication that does not depend on a single vendor.
Mattermost is open source and self-hostable, aimed at developers but suitable for any team, with apps for all major platforms. If you'd rather not run it yourself, Stackhero, a French managed cloud provider, offers a managed Mattermost instance.
Rocket.Chat is another open source option, with self-hosting guides for platforms including Docker and Kubernetes and clients across desktop and mobile.
Nextcloud Talk is the open source chat and video conferencing component of the Nextcloud Hub, self-hostable and built to integrate with existing systems.
Hosted chat platforms
If you want someone else to run the servers, just not an American company:
- Infomaniak kChat — a unified communication platform from Swiss cloud provider Infomaniak, with a free plan and EFTA hosting.
- Fleep — from Estonia, with many integrations and apps for iOS, Android, Windows, macOS and Linux. It has no built-in audio or video calls, but integrates with an external tool so you can start a call from the chat window.
- Nozbe — from Poland, with a free plan. It combines instant messaging, threads and kanban, and is developed mobile-first, with desktop apps also available.
- Private Discuss — from France, with a free plan and a strong focus on audio and video conferences alongside instant messaging.
The all-in-one option
Stackfield is a project management and collaboration platform from Germany, hosted in the EU. It combines team chat with task and project management, whiteboards, video conferencing and collaborative document editing. If you are considering replacing more than just chat — chat plus a tool like Trello, for instance — an all-in-one platform can simplify the move, at the cost of putting more of your workflow in one product.
What to weigh
- Migration: decide upfront whether chat history moves with you or starts fresh.
- Integrations: list the external tools your current chat connects to, and check each candidate before committing.
- Calls: if video meetings happen in your chat tool today, note that Fleep handles calls via integration rather than natively, and check whether that suits you.
Trade-offs are real here — smaller ecosystems, different interfaces, migration work. But the options above are mature products, not stopgaps.
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