Bluetooth chat in offChat
Bluetooth is offChat’s short layer: notes between nearby Androids, with no internet and no router.
What Bluetooth does here
When two Android phones with offChat can see each other on Bluetooth, a note can travel with no mobile data. Range is short and shrinks with walls, crowds and interference.
What it does not do
Bluetooth is not Wi-Fi Direct and it is not mesh. It does not cross a city. It needs a system permission and the radio on at both ends.