In step 6, we attach the textField to the query string in the URL but the code is looking for the textField/title in the response body as show in line 74.

The fix would simply put
{ "title":"{{TextField}}" }
in the web request body or put the appropriate key-value depending on the webhook

In "Step 6 - Complete Webhook Action Fields", the image indicated the web request to be GET. But route accepts only POST. Editting the image may be annoying so adding a little note may be enough instead.

Hello, I've been following your tutorials and I've getting a 504 error on Heroku:

I got the same using http or google assistant.

Thanks for you great job with this.