Don’t Set max-age Too Far In the Future!

Eric Lawrence, creator of Fiddler, put together an excellent post about issues with setting the max-age Cache-Control setting for too far in the future. Remember, setting max-age correctly in the Cache-Control header can improve web performance by instructing a client’s browser to keep the object in cache and refer to it for future requests.  This…


Capturing HTTP with Fiddler as a Reverse Proxy

My colleague on the ACE Performance Team, Vitaliy Konev, recently posted a blog post and video discussing how to set up Fiddler on a web server as a reverse proxy.  This is how you would capture HTTP traffic when you are not using a web browser client and you are also unable to configure the…


Creating Transactional Web Tests for Visual Studio with Fiddler / neXpert

One of the best features of Fiddler when performance testing is it’s ability to save a capture as a Visual Studio Web Test.  You can then use this web test to functional test or stick it in a load test to stress test your site. The latest version of Fiddler ( has an updated “Save…


neXpert ExecAction Listeners

neXpert v1.1 introduces many different ExecAction listeners for both general Fiddler actions and some neXpert specific actions. Command Action Sample Usage       loadsaz filename Load a SAZ file into Fiddler. loadsaz c:\blog.saz savesaz filename Save a SAZ file of all captured traffic savesaz c:\blog.saz clearcookies Clear all WinINET cookies. clearcookies clearcache Clear the…


neXpert mentioned in “Building High Performance Web Applications and Sites” at MIX09

John Hrvatin, a lead program manager on the Internet Explorer team, presented "Building High Performance Web Applications and Sites” at this years MIX.  In the talk he goes over many different aspects of web performance including: CSS performance Optimizing symbol resolution JavaScript coding inefficiencies HTTP performance Check out the video at


Setting Up Your Environment For Performance Testing

This rundown should help when using Fiddler for performance testing to perform captures correctly the first time.  If you have any feedback or additions to this list, please send them using the “Contact Us” link in the top left corner of the web page.  Thanks to Vitaliy Konev for some of the tips. Before any…


Introducing …. neXpert

What is it?  neXpert is an add-on to Fiddler Web Debugger which aids in performance testing web applications.  neXpert was created to reduce the time it takes to look for performance issues with Fiddler and to create a deliverable that can be used to educate development teams. neXpert can be downloaded here: A webcast…