WebAPI Model Binding from JSON
It looks as if it was mixing up form-urlencoded with json format - if you lookat the decoded string it is sending models= and then urlencoded JSON objects follow.
From my experience I think that your PUT end point declaration needs to look like this:
[HttpPut]public void Put([FromBody]IEnumerable<Product> models) { }So you need the FromBody attribute because your product array is in the body (I think?) and not in the url of the request.