Download and install Fiddler.
http://www.fiddler2.com/fiddler2/
Once installed, open it, click on the “Request Builder” tab located in the right side of Fiddler.
Insert this URL:
http://test.com/feed2/ODataService.svc/results
Note that you DO NOT NEED THE ?$format=JSON
In the “Request Headers” section, insert the following line:
accept: application/json
Hit the Big “Execute” button at the top right of Fiddler.
You’ll see the results of the request added to the list on the left side of Fiddler.
Double click on the request. The right side of Fiddler will change to the “Inspectors” tab where you can see the results of your request.
Also, since you are working with Json, you probably want to download and install the Json viewer plugin for Fiddler:
http://jsonviewer.codeplex.com/