Bluetooth Low Energy is presented in the Bluetooth 4.0 version, the main feature of this technology is low energy consumption. BLE technology works in the 2.4 GHz frequency band (ISM band) which contains 40 radio frequency channels, of which the last three channels are used for advertising and the remaining 37 are used for data transmission. The BLE system uses devices such as beacons, small, high-tech devices intended to send signals in a certain time interval with the goal of being detected by central devices that have scanning capabilities. The BlueUp Maxi beacons used in the final work have the possibility of configuration with the help of the Blue Beacon Manager android application in which we can configure the beacon settings. At the same time, we must pay attention to the configuration parameters so that the life of the battery is as long as possible and at the same time the functionality of our application is as high as possible. The main applications of BLE technology are locating users in indoor environment using the trilateration process based on RSSI values, which is not available to us using the GPS system, and for this very reason, the BLE system, along with technologies such as UWB and WiFi, is one of the solutions for this application. The BLE system is also used in the realization of a smart hospital, where with the help of beacons or smart tags we can track the location of medical staff, equipment and patients. With the help of React Native technology, there is the possibility of developing a mobile application on different platforms that allows us to track the user's location and scan beacons. It is important to note that the assessment of the user's location depends on the conditions in the indoor environment and the location of the beacon in the room.