Hello Pavan,
I'm using fiddler as my sniffer. First, open your sniffer. Then make a successful request to the website you want. It should be able to capture the HTTP Header(s) and HTTP Body needed. Say for example: Clicking on a thread in SDN after you open Fiddler would give a screenshot like the one below.
Based on that, you would know that it is using HTTP GET as a method. Cookies are used and that entity content type is using JSON.
Show us the HTTP Header of your receiving application so that we can help you more. 
Hope this helps,
Mark