Naven
Answers
Do you need to install anything to use Naven?
No. Naven is a web page. Opening navenapp.com in any modern browser is the entire installation, on a phone, a laptop or a school Chromebook.
There is no desktop application, no mobile app and no browser extension. Voice and video calls run in the browser too, which means the person on the other end of a call also installs nothing.
You can optionally add Naven to a phone's home screen, which gives it an icon and its own window and enables notifications that arrive when it is closed. That is a browser feature rather than an install, and on an iPhone it is the only way to receive notifications at all.
The trade is that a web app has less access to the device than a native one, particularly in the background.