MQTT:
MQTT (formerly the MQ Telemetry Transport) is a lightweight protocol that’s primarily designed for connecting power-constrained devices over low-bandwidth networks. Though it existed for over a decade, the advent of M2M (machine to machine communications) and Internet of Things made it a popular protocol.
Originally MQTT was invented in 1999 to connect oil-piplines over satellites by IBM. These satellite networks needed a lightweight and bandwidth-efficient protocol, which supports multiple Quality of Service levels. From 1999 to today the idea of MQTT has not changed, however, the primary focus of the protocol has changed from proprietary embedded systems to open Internet of Things (IoT) use cases.
Concept:
MQTT (=Message Queuing Telemetry Transport) is a publish-subscribe based messaging protocol. Data is published to a broker. This broker handels all data points in realtime. Every message to the broker is directed to a certain topic. Subscribing to these topics automatically will forward these messages to the subscribers (This is similar to the idea of twitter enabling hashtags to structure information). Topics can be structured in a hierarchy using a “/” to better organise different use cases. (e.g. streamsheets/example/test)
To get the full information go and visit their GitHub Wiki.
PS: Streamsheets locally uses the open-source Mosquitto Broker