Directory › Alternatives to Slack

European & open-source alternatives to Slack

6 European and open-source alternatives to Slack — privacy-friendly tools built and hosted in Europe.

Updated 8 Sep 2026 · refreshed weekly

A Matrix-based end-to-end encrypted messenger and secure collaboration app. It combines consumer messaging apps, collaboration…

An instant messaging application offering text and voice messages, two-way audio and video calls, and multi-person video…

An all-in-one project management and collaboration tool designed for organizations handling sensitive data, such as government…

Threema Work is a highly secure and user-friendly communication solution for businesses, offering team chats, voice/video calls…

Open-source team collaboration suite (chat, drive, tasks) by France-based Linagora.

A secure collaboration platform that offers encrypted messaging and communication tools for businesses and individuals, focusing…