Debugging messages in Node-RED

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Debugging messages in Node-RED

A spider enjoys having a juicy fly or other insect in its web. But there is no place for a bug in your little programme. Work out all the bugs, or glitches in the code, from your HARDWARIO projects. 🐞 We will show you how to do that.

What is a debug?

Among programmers, a debug means tweaking or error elimination in a programme. There’s always some little flaw to be found in a code.

For tweaking, programmers use a tool called debugger. It monitors the flow of a programme and notifies the programmer when it detects an error. An IT guy doesn't have to dig through all the code lines, because he knows where to look. You can find a simple debugger in your Playground. You can check in it if your programme works as it should, and discover possible flaws.

How to debug in Playground?

  1. It’s easy. 😎 Click on the Functions tab and look for a Debug node. It’s the first node in the Output section and looks like this:


  1. Connect the Debug node right behind the initial MQTT node. You don’t have to connect it to anything else, so it will be this solitary point in your programme (but don’t worry, it is an introvert, he likes it 🤓).

Our tip: Instead of to the MQTT node, you can connect the Debug node to any other node with the output on the right. This way, you will find out how particular features of your programme work. 👍


  1. Now, click on the bug icon in the upper right part of the Playground. 🐞


  1. And now you are in the debugger! In this bug tab you will see messages about functioning of your programme. For example, if you have the box with a button, try to press the button or put it in the fridge and watch what messages will show up in the debugger.

Based on these messages, while making future programmes, you can verify that everything works as it should. 👌 For example, if there is a connection between some nodes missing, debugger will alert you.

This is how the messages about what your programme does with the box look like in the debugger: