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neXpert is an add-on to Fiddler 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.

What features does neXpert include?

  • Add step markers while capturing traffic to demarcate steps or clicks in a scenario
  • Add easy access buttons for performance testing with Fiddler
  • Ping each host in a capture to calculate current latency
  • Create rudimentary response time predictions for different latencies and browsers (BETA)
  • Create a HTML report which checks for performance issues with the following:
    • HTTP Response Code
    • ASP.NET View State
    • Static Files
    • Large Images
    • Compression
    • Authentication
    • ETags
    • Cache Headers
    • Connection Header
    • Vary Header
    • Cookies


Install neXpert from here.


1.     Set up Fiddler environment
To use Fiddler to correctly profile a web application the following two settings must be enabled:

-    Reuse connections to servers
-    Reuse client connections

These settings can be found under the Tools/Fiddler Options menu and in the General tab.  Fiddler must be restarted after these settings are changed.

2.     Prepare to capture
With Internet Explorer closed, click the "Clear IE Cache" button on the neXpert tab to provide an empty cache for the capture.  Then be sure to turn on streaming mode and concurrent ping by verifying that both buttons on the neXpert tab read "Turn off"

3.     Perform capture
With Fiddler capturing, perform the first step in the scenario.  After all objects have loaded use the step description box to describe the click and click the "Add" button.

4.     Create report
Highlight all sessions in the capture with CTRL-A.  Click the "Create Report" button.

5.     Improve your site!
To learn more about the neXpert options and features, check out the help file which can be accessed from the neXpert menu in Fiddler.

Usage Instructions

Learn more over on the neXpert blog.

A webcast demonstration of neXpert is available.


neXpert UI

Output Report

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