The WebSocket protocol was designed to work well with the existing web infrastructure. As part of this design principle, the protocol specification defines that the WebSocket connection starts its life as an HTTP connection, guaranteeing full backwards compatibility with the pre-WebSocket world. The protocol switch from HTTP to WebSocket is referred to as the WebSocket handshake.
As we can see, there are various options available for communication between smart devices and the cloud. Of them all, MQTT (secure) is the most popular and you would see a lot of platforms and solutions preferring MQTT to other protocols.
Of course, there is always raw TCP/IP communication, but this would mean we would end up implementing the entire device ...
