Smart Street Light is an IoT web application designed for controlling and diagnosing LED streetlights. Utilizing the MQTT protocol, it facilitates communication with cabinets, which in turn interact with individual poles via the LoRa protocol. The application displays all cabinets and poles on an interactive map. It offers both manual and automatic control, with automation based on sunrise and sunset or a selected operational mode. The system is equipped to measure various parameters and provide detailed reports on errors and malfunctions.