What is MQTT

MQTT

Message Queuing Telemetry Transport is a lightweight, publish-subscribe network protocol that transports messages between devices.
The protocol usually runs over TCP/IP. 

In my opinion, it’s a protocol that was widely used in IoT(Internet of Things).

MQTT clients

Normally, it’s a bunch of micro-controllers that have WiFi access.
Like ESP32, ESP8866.

MQTT broker

It’s the service that runs on servers(or clouds).
Many big companies offer such a platform that allows your MQTT clients to connect.
It’s a middle software that transfers your data between MQTT clients.

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