How to specify POST payload for Rest Tasks?

Thanks for your answer. In fact, I’m seeking to build a Rest payload for a POST request in my BPMN task.

I had a look at this topic :

and it looks that @StephenOTT found how to concatenate a JSON payload for his POST call after getting his process variables.
But when I start my process (by REST) with a submit start form with my process variables, I see that variables that were used in payload script have null values in cockpit while I gave it a dummy value to test it.

In case this works like a response handling JS, I gave the script the name of a my variable “payload” (a string to contain the Json). But I can’t get this working to call my REST api. I also added Content-Type application/json to my headers.
Here is my BPMN : testRest.bpmn (8.0 KB)

Where is the problem from ? :neutral_face: