Is there any good tutorials for doing this with either XAMPP or Postman?

The best way I know how is to use fiddler to capture a normal request to http://bungie.net. The bungie website automatically makes a few other calls, which fiddler can capture, and you can get the cookies you need. Then simply copy/paste the raw fiddler request to a new request (using the composer tab), changing your api key. Quickest way to make requests imo. Easier to set up the first request this way. Edit: The request I look for is this: GET https://www.bungie.net/Platform/User/GetBungieNetUser/?lc=en&fmt=true&lcin=true HTTP/1.1