What I want is to make a web/mobile app (I've chosen Flutter) that acts both as a host and as a client, so multiple instances of this app can share data without actual back-end (let's say the addresses of the devices are hardcoded into the app for the simplicity).
I can't use Firebase or Backendless, my app has to be the only host. I've looked into socket.io, websockets, WebRTC and didn't find a solution.
So, is it even possible? With or without Flutter.
It is in theory possible, if you are planning to only use android you can use this library Flutter p2p which use wifi-direct (Android documentation) to discover devices and connect to them. It has some problems with newer environments but there is lots of forks from the git project that you can import. I've read that it should be possible to allow devices that doesn't support wifi-direct to connect if you create a group so maybe it could work for iOS if there is a hosting android device.
