+1 for Syncthing. I've been running it for years, after my student discount for Dropbox expired (Google drive and OneDrive were just getting traction at the time).

The mobile experience last I tried was pretty rough though. I don't really need my files on my phone and I have a web interface on my home server I can use to grab them in a pinch, but it's something to keep in mind.

If you’re on iOS, try my (FOSS) app for Syncthing: https://github.com/pixelspark/sushitrain

Android unfortunately.

Cool app though!

Unfortunately not available in my country (Malaysia)

Why did you restrict it by country? I’m in the EU and can’t install it.

You are most likely in France: your government does not allow publishing an app containing cryptography (in this case, Golang's crypto implementations and a package used by Syncthing - only using iOS libs should be fine) without authorization (which can only be obtained through French forms, at which point I'd want a French lawyer to be involved, so no).

You could of course build the app yourself from source.

Syncthing is easily the most effective FOSS I actively use. It just works and runs on everything.

Syncthing is great, but no good for mobile devices if you want to store and access lot of large files - it syncs everything, and last I checked, the features to prevent that were depreciated.