Simple example using the socketIO library on ESP 32 boards.

After setting up Arduino IDE to accept ESP32 devices (if you didn't, try this tutorial):

1. Install the WebSockets by Markus Settler library on your IDE with Sketch > Include Library > Manage Libraries...
2. Install the Socket IO Client library available on this repository. Note: I've tried to use the version available on the library manager of Arduino IDE but I got some error messages on console. So, I had to download and install the .zip from the last commit of the library repo (I've used this commit).

After those two steps you are ready to go!

If you want to make a quick test, you can use the server folder! Check that out!