
NextCloud
Free and open-source software. E2EE plugin not recommended.
Features
Online office
Integrated with a full-suite online office service
Larger ecosystem
Offers meetings, chat or productivity tools within their ecosystem
Zero Knowledge Encryption
Default settings provide zero-knowledge end-to-end encryption for data stored
Platforms
Windows
Compatible with Windows operating systems
Mac OS
Compatible with macOS computers
Linux
Compatible with Linux operating systems
Browser
Accessible through any web browser
Android
Available on Android mobile devices and tablets
iOS
Available on iPhone, iPad, and iPod touch