HTTP GET with Message Payload!

dear all:
I want to control a LED Server by GET method, which can turn LED on/off and get the LED state form server via HTTP response. This idea was verified by Node-RED and work well:

As above,when ON/OFF Button is click, a get request is send to server with payload(/? ON or /? OFF). By analysis the payload, the MCU of sever can set LED's state and response it to client!

Now, I am trying to porting this idea to App Inventor such that LED server could be controlled by phone!

But I do not know how to add the payload to the get request when use web component of App Inventor.

This is my first post. Looking for help. :hugs:


There is a very similar project at

Beware of the space between the '?' and 'ON' or 'OFF'.
Spaces are not allowed in URLs, and must first be replaced with %20 manually or by one of the Web1 encoding blocks (I can never remember which one.)

Better yet, don't use spaces in your URLs.

Thanks for your answer, I will try it.