4 open source alternatives to Microsoft Teams
Video, chat and collaboration bundled with Microsoft 365. Here are the open source projects real teams use instead — ranked by fit, with honest pros and cons for each.
What people don't love about Microsoft Teams
- Deeply tied to Microsoft ecosystem.
- Resource-heavy desktop client.
- Chat and meeting features sprawl across tabs.
Current Microsoft Teams pricing (for reference): Included in Microsoft 365 from $6.99/month; Teams Essentials from $4/user/month standalone.
Quick comparison
| Alternative | Best for | License | Self-host | Hosted cloud? |
|---|---|---|---|---|
|
Mattermost Slack-style open source team messaging. |
Enterprise teams needing Teams-like structure with compliance controls. | AGPL-3.0 / Apache-2.0 (modules) | ★★★☆☆ | Yes |
|
Element (Matrix) Decentralized messaging on the Matrix protocol. |
Federation plus end-to-end encryption for regulated industries. | Apache-2.0 | ★★★★☆ | Yes |
|
Rocket.Chat Open source team and community chat with video and voice. |
Large organizations with omnichannel and complex permissions. | MIT (community); proprietary modules available | ★★★☆☆ | Yes |
|
Zulip Threaded team chat with topics. |
Async-heavy teams that want topic-based threading. | Apache-2.0 | ★★★☆☆ | Yes |
1. Mattermost — Enterprise teams needing Teams-like structure with compliance controls.
Slack-style open source team messaging.
Strengths
- Familiar Slack-like UX.
- Strong self-hosting story and enterprise features.
- Good permission and compliance controls.
Weaknesses
- Some advanced features require paid tier.
- Mobile app performance is acceptable but not stellar.
- Larger install footprint than lightweight chats.
Mattermost homepage · Source on GitHub · Microsoft Teams vs Mattermost →
2. Element (Matrix) — Federation plus end-to-end encryption for regulated industries.
Decentralized messaging on the Matrix protocol.
Strengths
- Fully federated — you own your data.
- End-to-end encryption by default.
- Bridges to Slack, Discord, WhatsApp, etc.
Weaknesses
- Self-hosting Synapse or Conduit server is work.
- E2E encryption UX (device verification) can confuse users.
- Cross-signing and key backup setup is fiddly.
Element (Matrix) homepage · Source on GitHub · Microsoft Teams vs Element (Matrix) →
3. Rocket.Chat — Large organizations with omnichannel and complex permissions.
Open source team and community chat with video and voice.
Strengths
- Federation support (via Matrix bridge).
- {'Large feature set': 'channels, threads, omnichannel.'}
- Strong customization options.
Weaknesses
- Can feel heavy for small teams.
- Past performance issues on large deployments.
- Resource footprint is higher than competitors.
Rocket.Chat homepage · Source on GitHub · Microsoft Teams vs Rocket.Chat →
4. Zulip — Async-heavy teams that want topic-based threading.
Threaded team chat with topics.
Strengths
- Topic-based threading prevents channel noise.
- Great for async and open-source communities.
- Powerful search and history.
Weaknesses
- Topic model has a learning curve.
- Smaller ecosystem of third-party integrations.
- UI feels less polished than Slack.
Zulip homepage · Source on GitHub · Microsoft Teams vs Zulip →
Not what you're looking for?
Browse other tools in Team Communication, or check out open source projects by category on the full category index.