I am looking to develop a custom SDK / framework for peer to peer mobile device discovery and data transfer. The SDK should be able to detect the proximity of the peer devices (RSSI) and update data in realtime. I require it to be developed for both iOS and Android platforms and it must also work cross-platform. It has to work without internet dependency.
Some examples are p2pkit, Hypelabs, NewAer, Bridgefy, etc.