MQTT is a protocol for machine-to-machine communication that was invented in 1999 by Dr. Andy Stanford-Clark (IBM). Because of its lightweight nature, it is especially useful when used with microcontrollers for IoT projects. It is lightweight in terms of both energy consumption and bandwidth because it does not have much overhead, which makes it a great fit for battery-powered projects on microcontroller boards.
MQTT is used in a wide range of projects, from small-scale DIY home automation to applications in the healthcare sector, where practitioners use it to communicate with medical devices (for example, blood pressure monitors); and by oil companies to monitor miles of pipelines. Even Facebook uses it for its Messenger app.
In 2014, MQTT 3.1.1 was officially accepted as an OASIS standard, which sent out a great signal to everyone who was already using or...