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Using Fiddler to collect communications data for Web Capture applications

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Question / Problem: 

How do I use Fiddler to trace internet communications to troubleshoot Web Capture Applications?

Answer / Solution: 

Fiddler is a tool for tracing Internet communications, and is a key tool utilized by support to trace Web Capture communication and troubleshoot Web Capture applications. The .SAZ files produced by Fiddler provide all of the relevant Web Capture communications.

Often times, while assisting customers with troubleshooting, support will request a Fiddler log.

To capture a Fiddler Trace:

  1. Download and install Fiddler (see "Acquiring Fiddler" below)
  2. Once you have this tool installed please run it
  3. Once Fiddler is running please open a browser and recreate the issue you are reporting to the support staff
  4. Once you have reproduced the issue in the web browser please switch back to Fiddler and open the "file" menu and choose "Save -> Session(s) -> in Archivezip"
  5. Once you have the zip file please attach it to your case


  1. If you are running your application through localhost, you may need to point to "localhost." (with a period) for Fiddler to properly capture the traffic.
  2. If you are troubleshooting a web app that is hosted over HTTPS, please see the section on HTTPS below

Acquiring Fiddler:

The first step for using Fiddler is to download and install it. The following link will take you to the official download page for Fiddler. You will be presented with two options - a .NET 2 compatible installer and a .NET 4 compatible installer. Which version is required depends on the .NET runtimes available on the machine being used to browse the site. Generally, use the Fiddler2 link for an installer compatible with Windows 7.0 and earlier, and the Fiddler4 installer for windows 8.0 and newer.

After downloading, simply run the installer.

HTTPS Support

Please note that it's not recommended to capture over SSL if it can be avoided. It is recommended to implement non-https for the testing/debugging of an app rather than having to add the cert below.

In order for Fiddler to be able to make sense of encrypted traffic, you will need to allow HTTPS decryption:

By default, Fiddler will capture all web traffic on your machine while it is running. However, if you're troubleshooting on a site that is encrypted using HTTPS, You need to configure Fiddler to decrypt https traffic.

Decryption of HTTPS traffic requires that Fiddler register a special SSL certificate that is not malicious, but it's good practice to disable the cert when not actively using it for HTTPS troubleshooting.

Applies to:  

Product Version
Kofax Web Capture 11.1
Kofax Web Capture 11.0



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