title: How to authenticate SharePoint Rest API calls from c# back end? (Read details)
body: <p>I am trying simple application which listens for http requests and makes rest api calls to Sharepoint 2013.</p>
  
  <p><strong>Scenario:</strong></p>
  
  <hr>
  
  <p>A user makes a get request from the browser to the back-end (which is in c#). The sharepoint api is called from back-end. Now it should use the logged in users credentials for this request but I get unauthorized error.</p>
  
  <p>Calling rest api directly from browser works.</p>
  
  <p>Note :
  Users are authenticated with AD so I don't want to request credentials again in my app.
  Most solutions that I find assume that user is logged in on the machine making rest calls (back-end) but its different scenario.</p>