It’s common knowledge that the two key factors for improving the speed and performance of your web applications are:
HTTP caching is one of the best ways to reduce roundtrips and bytes transferred. Caching provides a mechanism for a client or proxy to store HTTP responses for later use, so that requests don’t need to cross the network.
An HTTP/304 response crosses the network much more quickly than if the full resource had been re-downloaded since it contains only headers and no body. However, even an HTTP/304 requires a full roundtrip to the web server; by carefully setting response headers, a web application developer can eliminate the need to issue even conditional requests.
Fiddler exposes the Cache-Control and Expires headers for you to quickly evaluate if your application is receiving and sending back to the web server the appropriate caching information, this way guaranteeing optimum cache behavior and minimum transactions between the server and your application.
What’s more, you can choose to compress certain HTTP responses in order to further limit the amount of bytes being transferred to the server.
Check out Fiddler’s Statistics tab to get an idea of your app’s overall performance metrics. You can select all sessions to see the total number of requests and bytes sent and received, broken down by content type or in a pie chart. By exposing all HTTP(s) traffic, Fiddler easily shows which files are used to generate a given page: users can multi-select the number of requests and bytes transferred to get a "total page weight".
The best way to impress your web site’s first time visitors is to deliver fewer and smaller files. A couple of tips for achieving better app performance:
Once you've tuned your site for a fast first visit, you can make it even faster for returning users by taking advantage of HTTP caching.