How to use a different proxy for some sites and fiddler for others


Product Version 5.0.20194.41348
Product Progress® Telerik® Fiddler™


In some cases, when using Fiddler it may be necessary to allow traffic through to an upstream proxy. If this is needed, follow the below solution.


  1. Configure the OS Auto Proxy settings with a PAC file and with Fiddler's Proxy configuration.

    System OS Auto Proxy Settings with Fiddler

  2. Use a catch in the PAC file.

    function FindProxyForURL(url,host){
        // Catch specific URL
        if (shExpMatch(url,"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx")){
            return "PROXY xxxxxxxxxxxxxx";
        // Let other URLs use fiddler
        return "PROXY localhost:8888";
  3. Start Fiddler with -noattach flag.

    fiddler.exe -noattach
  4. Set Fiddler Gateway Options to No Proxy to prevent infinite loop.

    Fiddler Gateway No Proxy

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