Fluxer vs Mattermost

Comparing two open source alternatives to Discord and Slack. Use the comparison below to decide which one fits your needs.

Fluxer

AGPL-3.0

A free and open source instant messaging and VoIP chat app for friends, groups, and communities.

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Mattermost

Mattermost is an open source platform for secure collaboration across the entire software development lifecycle..

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Side-by-side comparison

	Fluxer	Mattermost
License	AGPL-3.0	—
Self-hostable	Yes	No
GitHub Stars	10,599	39,355
Forks	814	9,053
Open Issues	147	1,092
Last Commit	Oct 16, 2026	Oct 16, 2026
First Released	Jan 1, 2026	Jun 15, 2015
Categories	Team Chat & Messaging Tools	Team Chat & Messaging Tools
Tags	#chat #messaging #voice chat #community #self hosted	—

GitHub stars over time

Fluxer

Mattermost39,355

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