NodeRed an Introduction

NodeRed can be run as a standalone product or an add-on to homeassistant.  It is a graphically based automation programming platform. 

NodeRed is based on "nodes" which are graphically based functions which can be linked together in a "flow".  This allows you take information in from a node and do something with that information.  An basic example of this might be to have a node which is listening to the output from  a motion sensor which in turn triggers a light to go on.  

The main advantage of using NodeRed over the default automation routines offered by HomeAssistant is the near limitless functionality functionality it offers, especially when paired with HomeAssistant.