ONLYOFFICE
An office suite with strong Microsoft format compatibility, available self-hosted.
Cost
Free to start, paid to go further
Free community edition; paid tiers for enterprise features.
Open source
Yes
The code is public. Anyone can inspect it, and it cannot be taken away from you.
Your data
Stays on your computer
Nothing is uploaded. This matters for anything confidential.
Use it for this
Teams that need .docx and .xlsx fidelity without Microsoft 365.
Do not use it for this
Single users who just need to open a file — LibreOffice is lighter.
A moment where you would reach for it
Collaborating on spreadsheets where the formatting has to survive round trips to Excel.
How hard is it to pick up?
Straightforward, but expect an hour of figuring it out.
Other things that do this job
No tool is best at everything. These solve a similar problem, with different trade-offs.
About this entry
Checked on 1 Sept 2026. Prices and free limits change without warning, and often quietly. Treat everything above as a starting point and confirm on the official site before you rely on it.
Nothing here is sponsored. A tool appears because it solves a real problem, not because someone paid for it to be listed.