The technology relevant for the Internet of Things (IoT) devices to communicate effectively is MQTT (Message Queuing Telemetry Transport). MQTT is a lightweight messaging protocol designed for small sensors and mobile devices, ensuring low-bandwidth and high-latency communication. It enables devices to send and receive messages efficiently, facilitating real-time data exchange in IoT applications. MQTT is particularly useful in scenarios involving remote monitoring and automation, where reliable communication is critical for operation.