Node-RED can be used to connect devices and services in an IoT system by providing a visual, drag-and-drop programming interface for wiring together hardware devices, APIs, and online services.
For example, Node-RED can be used to connect a temperature sensor to an IoT platform such as AWS IoT Core. The user can create a Node-RED flow to read the temperature data from the sensor and then send it to the AWS IoT Core platform. The user can also create a flow to receive commands from the IoT platform and send them to the temperature sensor.