REST is a series of principals used to structure APIs. Think about if you had a lot more lights on your Raspberry PI. A simple way would be having a call lighting up a specific light. But then the client must track state, in terme of rembering which lights are lit. In a REST sister, you&#x27;d request the state of all the lights (typically through a GET http request), which the server would track for you. Then you&#x27;d send back the lit or unlit state of all the lights, thereby setting a new state (typically, again, through an http POST request).