Best Open Source Alternatives to Microsoft Teams

Compare the best free and open-source alternatives to Microsoft Teams — self-hosted and desktop replacements you fully control, ranked by GitHub stars, license and platform support.

Curated by open-source.store · Updated August 2026 · 5 alternatives

Microsoft Teams

Proprietary SaaS

PricingFreemium

Platformsweb, mobile, desktop

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Microsoft Teams alternatives compared

Open-source alternatives to Microsoft Teams, compared by stars, license and platform
Tool		License	Platforms	Self-hosted
Rocket.Chat	45,914	MIT	LinuxmacOSWindowsDocker	Yes	Aug 2026	Visit
Mattermost	38,632	AGPL-3.0	LinuxmacOSWindowsDocker	Yes	Aug 2026	Visit
Zulip	25,591	Apache-2.0	LinuxmacOSWindowsDocker	Yes	Aug 2026	Visit
Matrix Synapse	12,109	Apache-2.0	LinuxmacOSWindowsDocker	Yes	Apr 2024	Visit
Revolt	3,183	AGPL-3.0	LinuxmacOSWindowsDocker	Yes	Jul 2026	Visit

Top open-source Microsoft Teams alternatives

Rocket.Chat45,914MIT

Omnichannel open-source customer and team chat hub built with Javascript.

LinuxmacOSWindowsDockerWeb

vs Microsoft Teams: a free, open-source option you fully control, licensed MIT.

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Mattermost38,632AGPL-3.0

Secure open-source developer collaboration and chat platform built for technical teams.

LinuxmacOSWindowsDockerWeb

vs Microsoft Teams: a free, open-source option you fully control, licensed AGPL-3.0.

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Zulip25,591Apache-2.0

Async-oriented team chat software offering structured email-like threaded messaging.

LinuxmacOSWindowsDockerWeb

vs Microsoft Teams: a free, open-source option you fully control, licensed Apache-2.0.

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Matrix Synapse12,109Apache-2.0

Reference homeserver implementation for secure, decentralized Matrix network messaging.

LinuxmacOSWindowsDockerWeb

vs Microsoft Teams: a free, open-source option you fully control, licensed Apache-2.0.

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Revolt3,183AGPL-3.0

Open-source community server alternative to Discord built with Rust and TypeScript.

LinuxmacOSWindowsDockerWeb

vs Microsoft Teams: a free, open-source option you fully control, licensed AGPL-3.0.

Visit Details