There is no RESTful JSON with multipart. Each “parameter” is a form part (as if someone is submitting a web form).
I’ve found the CURL documentation most helpful in giving an overview of the -F parameters and how they are constructed. You can then decide “aha, this is something someone else has already written, I don’t need to write my own http browser just to send an API some data.”
Ahhhhh! OK now I got it!
So no JSON structure to send as payload,
The OpenAI API reference doc should be clear about this.
It’s not obvious.
Thanks a lot, will try now.
Seb