When you develop a program in Node-RED, it’s called a flow. The Hello World of Node-RED flows consists of a button that, when clicked, outputs a timestamp to the debug console. We’ll start with this simple flow so you can get comfortable with the Node-RED interface before we move on to developing an HTTP API.
To begin, take a look at the left pane of the Node-RED interface. This shows the kinds of nodes you’ll use to construct flows, categorized by their purposes.
Input nodes act as sources of events into the system. You can tell an input node visually by the tiny gray rectangle protruding from its right-hand side. This gray rectangle is an output port.
If you hover over a node, a tooltip will pop up to give you more ...