The nRF Sniffer for Bluetooth® LE is a useful tool for learning about and debugging Bluetooth Low Energy applications. It provides a near real-time display of Bluetooth packets that are sent between a selected Bluetooth Low Energy device and the device it is communicating with, even when the link is encrypted.
When developing a Bluetooth Low Energy product, knowing what happens over-the-air between devices can help you identify and fix issues quickly.
On startup, the Sniffer lists all nearby Bluetooth Low Energy devices that are advertising, providing the Bluetooth address and address type, complete or shortened name, and RSSI.