MQTT or Message Queue Telemetry Transport is a protocol focused on applications in M2M (Machine-to-Machine Interaction) and IIoT (Industrial Internet of Things) systems. Information transfer to MQTT is implemented according to the Publisher/Subscriber scheme and occurs through an intermediate server (Broker). The data source (Publisher) sends data to the server (Broker), other systems and devices, being Subscribers, read them from there.

This method of interaction is well suited for event-based messaging, when the devices themselves periodically communicate. In version 4.0 WebHMI has the ability to work in both Broker and Publisher/Subscriber mode, so it can be used as an IoT Edge gateway to integrate the monitoring object into large IoT solutions such as “smart city”, etc., or on the contrary, to receive data from remote devices (sensors) via the Internet, without the need to integrate IP networks.