KBA-01705: Using Telerik Fiddler to Capture HTTP Traffic


Fiddler is a free web debugging tool that logs all HTTP(S) traffic between a computer and the Internet. Spitfire Support uses Fiddler to record conversations between a workstation and IIS. Anyone can run Fiddler on his or her workstation.

Fiddler is available as a free download.


On an non-SSL (HTTP) site:

  1. Download and install Fiddler.
  2. Run Fiddler before you run sfDash (Spitfire).
  3. Continue with the Capturing Your Session steps below.

On an SSL (HTTPS) site:

  1. Download and install Fiddler.
  2. Select Tools | Options to get to the HTTPS tab.
  3. On the HTTPS tab, check Decrypt HTTPS traffic, then OK to confirm.
  4. Leave for all processes alone.
  5. Set the bottom box to Perform decryption (click the underlined words to select Perform decryption).
  6. In the box, enter *.yourdomain.com
  7. Click the OK button.
  8. Close Fiddler.
  9. Reopen Fiddler, start your Spitfire (sfDash) session and continue with the steps below.

Capturing Your Session

  1. With Fiddler running, reproduce the issue in Spitfire as simply as possible.
  2. In Fiddler, select File | Save | All Sessions. Include the case number in the saved-file name.
  3. (optional) You can highlight rows in the trace file and prune it down.
  4. Send the .saz file to Spitfire Support.
  5. Close Fiddler.


  • Try to keep your Internet activity limited while using Fiddler or the trace will be very large.
  • Keep in mind that personal data may be captured. Avoid leaving Fiddler open for extended periods.

KBA-01705; Last updated: December 20, 2017 at 13:28 pm