Node-RED or Plynx for an ESP32 dashboard on your phone

Two different starting points

With Plynx you start on the phone. The app is where you build the dashboard. Your ESP32, ESP8266 or Arduino runs a small library, and the widgets on your screen are bound straight to pins on the board. There is no web page to lay out and no server you have to run yourself, although you can if you want to.

With Node-RED you start on a server. You install it on a machine that stays on, often a Raspberry Pi, and you build your logic as a flow in the browser. The phone comes at the end: the Node-RED dashboard is a web page, and you open it in Safari like any other site.

Both are free. Plynx is a free app with no ads, no subscription and no in-app purchases, and its Arduino library is MIT licensed. Node-RED is open source under Apache-2.0 and is still actively developed.

Where a phone app is the better shape

The Node-RED dashboard works in a browser, but it stays a browser tab. It does not become a Home Screen widget, it does not show a value on your Lock Screen, and it does not have an Apple Watch app. Plynx has all three, along with more than 30 widget types and dashboards that keep the last known values when a board goes offline.

Node-RED also needs looking after. There is a host to keep running, updates to apply, and usually an MQTT broker running next to it. With Plynx you can start on the free public server and never think about hosting, or move to your own server later. The Plynx server is a single JAR file and runs on a Raspberry Pi if you want the data to stay at home.

And with Plynx the sketch stays yours. You write Plynx.virtualWrite(V0, celsius) in your own code and a gauge moves. Nothing in the middle has to be running for the value to exist. When you have a question about the board, Archimedes, the assistant inside the app, can read the pin you are asking about before it answers.

What Node-RED does well

Node-RED is at its best when the interesting part of your project is the logic. If you want something like “when the tank drops below 20 percent and it has not rained since Tuesday, run the pump for ten minutes and send me a message”, a flow is a natural way to express that. Plynx has rules and automations too, but they belong to one project and are kept simple on purpose.

It also connects to almost anything, with thousands of community nodes for MQTT, HTTP, serial ports, databases and most commercial services. And a debug node shows you the payload at each step, which is a real help when something breaks.

What Plynx does not do

Plynx is iPhone only. There is no Android app you can install today, so if your household uses both, that settles it and a browser dashboard is the better fit.

The Apple Watch app talks through the iPhone, so the phone has to be nearby. Home Screen and Lock Screen widgets show the last value the app saw rather than fetching a fresh one at that moment, although tapping a button widget does send a real command to your board.

Push notifications only work through the public Plynx server. If you host the server yourself, the App Store build cannot receive push from it. And the automations that keep running while your phone is off are the ones that live on the server; anything based on your location naturally needs the phone.

A setup that works

A common arrangement is Node-RED and an MQTT broker on a Raspberry Pi for the automation that has to keep running, and Plynx for the two or three boards you want to check and control from the sofa. If you would rather have everything in one box, the Plynx server can run on the same Pi.