Solved
How to set different Content-Types in multipart/form-data POST Request?
I have a REST API, that I can curl correctly, but I can not get it done in ReadyApi. I have to upload a picture and a json string, which has the content-type "type=application/json": curl -X 'POST'...
I don't know, if it is the only solution, but I figured out, that you can attach the json as a *.json file and configure the content type in the attachements tab.
I really think, this needs improvement from Smartbear. Its very underwhelming to solve such basic config by such a workaround...
