Enable json compression in IIS

JsonCompression.xml

<system.webServer>
    <urlCompression doDynamicCompression="true" />
    <httpCompression>
      <dynamicTypes>
        <add mimeType="application/json" enabled="true" />
        <add mimeType="application/json; charset=utf-8" enabled="true" />       
      </dynamicTypes>
    </httpCompression>
</system.webServer>