3 open source alternatives to Microsoft 365
Office suite in the cloud — Word, Excel, PowerPoint. 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 365
- Subscription-only model for full features.
- Heavy client, frequent updates.
- Cloud storage quota included but limited.
Current Microsoft 365 pricing (for reference): Personal from $6.99/month.
Quick comparison
| Alternative | Best for | License | Self-host | Hosted cloud? |
|---|---|---|---|---|
|
ONLYOFFICE Open source office suite with excellent MS Office compatibility. |
Drop-in office suite with strong Word/Excel/PowerPoint compatibility. | AGPL-3.0 | ★★★☆☆ | Yes |
|
LibreOffice The classic open source office suite for desktop. |
Free desktop office suite with no subscription. | MPL-2.0 | ★☆☆☆☆ | Self-host only |
|
Collabora Online Browser-based LibreOffice for collaborative editing. |
Browser-based collaboration with LibreOffice engine. | MPL-2.0 | ★★★☆☆ | Yes |
1. ONLYOFFICE — Drop-in office suite with strong Word/Excel/PowerPoint compatibility.
Open source office suite with excellent MS Office compatibility.
Strengths
- Best-in-class Word/Excel/PowerPoint rendering fidelity.
- Integrates with Nextcloud, Seafile, WordPress, and more.
- Both desktop app and server editor available.
Weaknesses
- Document Server install is heavier than Collabora Online.
- Some advanced features require enterprise licence.
- Concurrent edit conflicts still occur occasionally.
ONLYOFFICE homepage · Source on GitHub · Microsoft 365 vs ONLYOFFICE →
2. LibreOffice — Free desktop office suite with no subscription.
The classic open source office suite for desktop.
Strengths
- Mature, trusted suite for desktop.
- No subscription — free forever.
- Strong ODF support and decent MS Office compatibility.
Weaknesses
- UI feels dated to some users.
- Collaboration requires Collabora/ONLYOFFICE server.
- Mobile version is read-focused.
LibreOffice homepage · Source on GitHub · Microsoft 365 vs LibreOffice →
3. Collabora Online — Browser-based collaboration with LibreOffice engine.
Browser-based LibreOffice for collaborative editing.
Strengths
- True LibreOffice engine in the browser.
- Plugs into Nextcloud, ownCloud and more.
- Strong at ODF-first workflows.
Weaknesses
- MS Office fidelity is good but below ONLYOFFICE in places.
- Requires integration with a file server (no standalone UI).
- Server resource usage is noticeable.
Collabora Online homepage · Source on GitHub · Microsoft 365 vs Collabora Online →
Not what you're looking for?
Browse other tools in Office & Document Editing, or check out open source projects by category on the full category index.