I was thinking of developing an offline app for android (and PC too, later) using HTML/CSS/JS for the user interface and some of the app logic. But I realised I didn’t know write to the filesystem in the background without using cookies (which are easily deleted by disk cleaners).

I want to use an Android application in a manner similar to servers like XAMPP. I want to be able to send requests to the application, mainly to read and write files, from an HTML/CSS/JS front-end.

Preferably, I would like to do this without things like React and Flutter.

I haven’t tried anything yet, because I don’t know where to start or if it’s even feasible.