Where is the "console", and its log?

I am following a Winsocket code example tutorial on RandomNerd, which works well. However, the source code includes statements like:

console.log(‘Connection opened’);

Whilst I can see the output from ‘serial.print’ statements on the terminal, I can’t see outputs from statements like the one above.

I know this will be an absurdly elementary question, but any recommendations for a beginner’s tutorial would be much appreciated. The Community ‘Get Started’ tutorials tend to be hardware-specific and mostly go over my head.

You mean the browsers console log? Depends on the browser. Usually right-click in empty space → Inspect (element) → console.


Are you working with PlatformIO for this project? Seems like a JavaScript / web development question to me.

Ah, I think you mean ESP32 WebSocket Server: Control Outputs (Arduino IDE) | Random Nerd Tutorials.

Thanks for the correction Max. Sorry, I meant ‘Websocket’, not ‘Winsocket’ and yes, the link you have given is for the tutorial I am working on. Yes, I am working with PlatformIO for this project.

I don’t know what ‘browsers console log’ means. If I right click on empty space on my iMac I don’t see ‘Inspect(element)’ as an option.

This is my query:

One of the functions in the tutorial source code in the above link is:

function onOpen(event) {
console.log(‘Connection opened’);

I would like to know where, when I run the code on my ESP32 board, using PlatformIO, I can see the words “Connection opened” so that I can confirm the code is working as expected.


If I read the tutorial correctly it’s about programming an ESP32 with a firmware that will open a webserver. When you open the website served by this webserver in your browser, the JavaScript transfered from the ESP32 to the browser runs in the browser. Part of the code is

  var gateway = `ws://${window.location.hostname}/ws`;
  var websocket;
  window.addEventListener('load', onLoad);
  function initWebSocket() {
    console.log('Trying to open a WebSocket connection...');
    websocket = new WebSocket(gateway);
    websocket.onopen    = onOpen;
    websocket.onclose   = onClose;
    websocket.onmessage = onMessage; // <-- add this line
  function onOpen(event) {
    console.log('Connection opened');

The console.log(x) will produce a log in the JavaScript console of the browser.

Refer to https://support.monday.com/hc/en-us/articles/360002197259-How-to-Open-the-Developer-Console how to get into that console for your browser. Everyone is a little bit different – Safari hides the setting additionally behind a checkbox.

That’s exactly it!
Many thanks Max for explaining this so clearly, you have helped me a lot. Thanks also for the link to the excellent website about using the browser console.