Run Fiddler as a Windows Service with AlwaysUp

How to Run Fiddler as a Windows Service with AlwaysUp

Capture HTTP traffic as soon as your PC starts, before anyone logs on

Fiddler is a free Web Debugging Proxy that intercepts all HTTP traffic between your computer and the Internet.

To setup Fiddler 2 to run as a Windows Service with AlwaysUp:

  1. Download and install AlwaysUp, if necessary.

  2. Download and install Fiddler, if necessary. Please make a note of where you installed it as we will need that location in a later step.

  3. Fiddler is designed with the expectation that a human user will be around to clear the traffic list once in a while, otherwise Fiddler's memory usage will grow unbounded. You can help ensure that Fiddler doesn't use crazy amounts of memory by using the "Keep only" dropdown in the toolbar to automatically trim the session list once it reaches a certain length [*].

    Limiting the number of sessions in Fiddler

  4. Start AlwaysUp.

  5. Select Application > Add to open the Add Application window:

    Add Application

  6. On the General tab:

    • In the Application field, enter the full path to the Fiddler executable, Fiddler.exe. If you installed Fiddler in the default location, this is

      C:\Program Files\Fiddler2\Fiddler.exe

    • In the Name field, enter the name that you will call your application in AlwaysUp. We have used Fiddler but you can specify virtually anything you like.

    • If you have any command line parameters for Fiddler, enter those in the Arguments field. You may want to specify the -quiet flag (to suppress prompts and alerts) but we recommend leaving that out for now, until after we get things working smoothly.

    Fiddler Windows Service: General Tab

  7. Switch to the Logon tab and specify the user name and password for the account where you installed Fiddler.

    Note that Fiddler only registers as the proxy in the user-account that it is running under. To get applications running in other accounts to send traffic to Fiddler, their proxy settings will need to be adjusted manually [*].

    Fiddler Windows Service: Logon Tab

  8. Click over to the Startup tab and check the Ensure that the Windows Networking components have started box. This informs AlwaysUp that Fiddler needs the TCP/IP networking stack properly initialized before it can start its work.

    Fiddler Windows Service: Startup Tab

  9. Click the Save button. In a couple of seconds, an application called Fiddler (or whatever you called it) will appear in the AlwaysUp window. It is not yet running though.

    Fiddler Windows Service: Created

  10. To start capturing with Fiddler, choose Application > Start "Fiddler".

    Fiddler Windows Service: Running

    On Windows 7, Vista and Server 2008, Fiddler will be running in the isolated Session 0. To see the Fiddler window, select Tools > Switch to Session 0...

    Fiddler Windows Service: Running in Session 0

    You can also see Fiddler by selecting Application > Restart "Fiddler" in this session, which will quickly stop it and start it again on your desktop.

  11. That's it! Next time your computer boots, Fiddler will start logging your web traffic immediately, before anyone logs on. We encourage you to edit the application in AlwaysUp and check out the many other settings that may be appropriate for your environment. The 70+ page user's manual (PDF) describes them all.

[*] Special thanks to Eric Lawrence, the developer of Fiddler, for reviewing this tutorial and providing invaluable insight!

Fiddler not working properly as a Windows Service?

  • From AlwaysUp, select Application > Report Activity > Today... to bring up a HTML report detailing the interaction between AlwaysUp and your application. The AlwaysUp Event Log Messages page explains the more obscure messages.
  • Consult the AlwaysUp FAQ for answers to commonly asked questions and troubleshooting tips
  • Contact us and we will be happy to help!

Download & Try it Free!

Download AlwaysUp and Run as a Service Today! Version 15.1

7.9 MB Installer
Our 12,000+ customers include...
Compatible with Windows 11 Compatible with Windows Server 2022 Compatible with Windows 10
Over 94,000 installations, and counting!
AlwaysUp is number 1! Run as a Service with AlwaysUp

Rock-solid for the past 19+ years!