Showing Result of http output plugin


I have the following output code that sends the results to an API

output {
  stdout {}
   http {
    http_method => post
    url => ""
    content_type => "application/json; charset=UTF-8"
    headers => ['x-access-token', 'xxxxxxxxxxxxxxxxxxxxI']

I've been told that the API should return the results of the API call including any error messages. However the only results I get are as follows

2015-11-18T10:28:21.382Z %{host} %{message}

Is it possible to output the results of the API call?