Many modern phones now allow paying for items using Near-Field Communication and there’s a react native library with active development for it; this protocol can also be used to connect two devices by proximity, meaning that users that have two devices (like me) that need them to stay in sync pretty much instantly at times, it would allow for this since it’s not syncing to a server but between local devices. This would also speed up syncing to the server since only one device would need to sync upstream and the other can just check it.
Bluetooth could be an alternative, but I’m not fully sure how this would work and know there are plenty of security holes there.
