Mattermost
Mattermost is a free, open-source messaging app for Android. Secure, self-hosted workplace messaging. It has 2,730 GitHub stars and is released under the Apache-2.0 license, and you can install it from F-Droid.
github.com/mattermost/mattermost-mobile (opens in a new tab)
- Official
- Android
- Messaging & chat
- Actively maintained
About Mattermost
Requires Mattermost Server v11.7.0+. Older servers may not be able to connect or have unexpected behavior. ------- Mattermost is secure workplace messaging from behind your firewall. - Discuss topics in private groups, one-to-one or team-wide - Easily share and view image files - Connect in-house systems with webhooks and Slack-compatible integrations To use this app, you need a URL for a Mattermost server. ------- Host your own server: Terms of Service: Contribute to the project:
Privacy and F-Droid
F-Droid builds Mattermost from its published source code and flags anti-features such as ads, tracking or reliance on non-free services.
No anti-features flagged on the latest F-Droid build.
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What is Mattermost?
Mattermost is a free, open-source messaging app for Android. Secure, self-hosted workplace messaging. It has 2,730 GitHub stars and is released under the Apache-2.0 license, and you can install it from F-Droid.
Is Mattermost free and open source?
Yes. Mattermost's source code is public on GitHub under the Apache-2.0 license, which is OSI-approved or FSF-free. F-Droid, which builds it from source, flags no anti-features such as ads or tracking on its latest build.
How do I install Mattermost?
You can install Mattermost from F-Droid (package com.mattermost.rnbeta); the links are on this page. Its GitHub repository also publishes releases (latest: release-2.44).
Is Mattermost still maintained?
The repository's most recent commit was on Oct 7, 2026. Its F-Droid listing was last updated on Sep 19, 2026. appsgit only lists apps whose repository had a commit in the last six months.