If you know Node-RED

Most of what you know carries over. You drag nodes onto a canvas, wire them, set properties and click Deploy. Messages carry payload and topic. Config nodes hold shared settings like an MQTT broker. The differences come from where the flow runs: on a microcontroller, not on a server.

Where the flow runs

The editor runs on your computer, but the flow runs on the board. Deploy compiles the flow to MicroPython and sends it to the board, which then runs on its own. Close the editor, unplug the USB cable, and the flow carries on.

Function nodes are Python

Function nodes run MicroPython, not JavaScript. A message is a Python dict, so write msg['payload'], not msg.payload.

if msg['payload'] > 30:
    msg['topic'] = 'alarm'
    return msg

Much else is the same. return msg passes the message on, and returning nothing stops it. Return a list to route to several outputs. context.get()/context.set() and flow.get()/flow.set() work as you'd expect. There's no global, since there's only one flow. See the function node.

Don't use time.sleep() in a function node. It stops the whole board, not only that node. Use await asyncio.sleep() or a delay node instead. See event-driven programming.

Messages

Every message needs a topic, even an empty one (''). Ports also have types, such as int, bool and string, and the editor refuses a wire between types that don't fit. See Editor in depth.

Nodes

The palette is smaller, and made for hardware. timer, interrupt, gpio out, pwm out and the sensor and display nodes work with the board directly. inject, debug, function, delay, mqtt, http and udp will look familiar.

You add node types by writing a JSON file and a Python file. See writing custom nodes.

Debugging

debug output appears in the editor's console, not a sidebar. An error in one node is reported in the console, saying which node, and the rest of the flow keeps running. See debugging.

Using both

Node-RED is the better place for dashboards, databases and cloud services. A common setup is Thingstudio boards publishing over MQTT to a Node-RED flow on a server or Raspberry Pi.

Next: getting started.