Using Fiddler to Examine Web Traffic
When building typical web applications using ASP.NET WebForms and ASP.NET MVC, the usual way of testing and debugging is to see whether the page loaded correctly (ie whether it displays the correct data or not). However, when building ajax applications / single page applications, you want to test not only the appearance of the page but more importantly the results of API calls. Since these results may not be obvious by just looking at the page, we need a different method of testing.