nRF Connect is a cross-platform tool that enables testing and development with Bluetooth low energy (previously called Bluetooth Smart). The tool allows for an easy setup of connections with other devices. You can use these connections for reading and writing to the external nodes.
nRF Connect is designed to be used in conjunction with the nRF51 DK, the nRF51 Dongle, or the nRF52 DK running a specific connectivity application. nRF Connect will automatically detect which kit is connected and upload the needed FW if not programmed into the kit already.