OnlyOffice
Office suite with strong Microsoft compatibility; desktop or self-hosted.
freemium offline open source
Get it →One-Time Purchase & Offline Alternatives to Microsoft 365 (2026)
Why people leave Microsoft 365
- Office is subscription-only; the perpetual license is deprecated and pushed aside.
- Documents nudged into OneDrive and the cloud by default.
LibreOffice
Full free office suite — documents, spreadsheets and presentations, offline.
free offline open source
Get it → Setup & migration guide → Free · pay what you want