List of web applications that use only JSON ( RIA applications )

I am looking for web applications that use only JSON client/server communication. For example, if client wants to POST new data to server then this POST should be in JSON but not "form-data" or "x-www-form-urlencoded" or user wants to edit smth and this edited data should be sent as a JSON to the server. And also the response should be in JSON. Does someone know these kind of open source or Bitnami ( https://bitnami.com ) applications? Thanks a lot in advance.