How to trade cards from one device to another?

Hi guys

I am trying to figure out a simple way of trading cards from one device to another, preferably without a server.

Is there no way for the game to listen to an event coming from another device? Maybe if they are on the same Wifi network? The devices would be close to each other, no trading if you can't physically see the other person (just like IRL trading cards you trade face to face)

I literally just want to be able to trade cards with other players, no security concerns just yet, simply sending a json object from one device to another that are in close proximity.

Keen to hear from you guys!