Build Json payload in HTTP Request Action module

I am using the “HTTP Request” action module in Flows to send (POST) a json payload to a third-party service. I was expecting to see an option to build the body of the request, as you can see it in the screen shot from this forum post: Flows "Custom HTTP request" data format issue - json being escaped

However, the “body” field is not available to me to edit and build for the request. Am I doing something wrong?

i have no idea, but did you click SHOW ALL FIELDS? Maybe its hidden in this view?

It’s not under “Show All Fields”…