Once I had gotten Fiddler to run (had to tell Mono to run in 32 bit mode) and I had re-created the settings.txt file, I received this error when trying to capture traffic:

Fiddler/FiddlerAttach.applescript:7:87: execution error: /bin/sh: USB,127.0.0.1,8888,on,127.0.0.1,8888,on,0,0,off,0,0,off: command not found (127)

This only occurs when double-clicking a SAZ file from Explorer when Fiddler isn't open.

v5.0.20182.28034 for .NET 4.6.1

---------------------------
Script Failure
---------------------------
Failed to load script.
 Microsoft.JScript.JScriptException: Type mismatch

   at Microsoft.JScript.Convert.CoerceT(Object value, Type t, Boolean explicitOK)

   at Fiddler.ScriptNamespace._Startup.Startup()

   at Microsoft.JScript.Vsa.BaseVsaEngine.Run()
Microsoft.JScript.JScriptException: Type mismatch

   at Microsoft.JScript.Convert.CoerceT(Object value, Type t, Boolean explicitOK)

   at Fiddler.ScriptNamespace._Startup.Startup()

   at Microsoft.JScript.Vsa.BaseVsaEngine.Run()   at Microsoft.JScript.Vsa.BaseVsaEngine.Run()

   at Fiddler.FiddlerScript._LoadScript(String sScriptFilename, Boolean bPlaySounds) in C:\JenkinsHome\jobs\FiddlerReleaseBuild\workspace\Fiddler2\Common\Application\Scripting\Scripting.cs:line 315

   at Fiddler.ScriptBase.LoadRulesScript(Boolean bPlaySounds) in C:\JenkinsHome\jobs\FiddlerReleaseBuild\workspace\Fiddler2\Common\Application\Scripting\ScriptBase.cs:line 198
---------------------------
OK   
---------------------------

 

This reproduces even when the FiddlerScript is basically empty, like so:

import Fiddler;

class Handlers
{

}

 

 

Sadly, because Fiddler's code has been obfuscated, it's difficult to see what caused this regression.

My Surface is work on 150% DPI , The App looks unclear.

THX

Response headers added from Fiddler-script (in reverse-proxy setup) are not sent to client. Even though the session shows them as sent. However, if I set a bpafter for that particular url it works! I Don't need to do anything else, just set the bpafter ang type 'g' to let it go. The client then see the response header.

Request a lighweight proxy forwarder like combination between Proxifier + AppContainer Loopback Excemption Utility in 1 desktop app. Since Fiddler is too heavy in CPU usage and Proxifier cannot forward any proxy to UWP desktop app (any apps from Windows Store).... no need extra feature but just a proxy forwarder like Proxifier + AppContainer Loopback Excemption Utility that works in any Desktop software environtment like OpenVPN adapter. Thanks.

The Tools -> HOSTS is a great feature, especially for situations that prevent local admin rights.  I find it difficult to know that the redirection is functioning when looking at the capture log.  It would be nice if something visual would standout to help draw attention that this rule was applied.

Thank you!

It would be really great to be able to view requests and responses as a formatted json string.  Currently, you can show JSON, which uses some tree format, and you can show raw, which is just a flat hard to use string.

It would also be great to be able to format json inside the request composer so it can be easy to modify.

I use Fiddler to compose requests in addition to tracing HTTP requests going through my machine. However, Fiddler really lacks in maintaining history of your previously composed requests. In this area, POSTMAN really shines, and therefore, some folks might move to POSTMAN. We don't have to have fancy features but the ability to organize your requests in the History will be much appreciated.

Hello,

I am getting the following error in fiddler and without Capture HTTPS CONNECTs it works, also in the Protocols I have enabled: <client>;ssl2;ssl3;tls1.0;tls1.1;tls1.2

fiddler.network.https> HTTPS handshake to <domain> (for #6) failed. System.Security.Authentication.AuthenticationException A call to SSPI failed, see inner exception. < The message received was unexpected or badly formatted

Win32 (SChannel) Native Error Code: 0x80090326

Ashen

[Edited by Telerik Staff to remove personal information and convert to bug report]

Some responses can not be shown in fiddler,for example,i am analysising the package of 植物大战僵尸2(pvz2) for ios.it shows "400 .net error response headers...",but other app like burpsuite can deal with it well...

 

so i've to set the proxy of iphone to "192.168.1.2:8080" and the gateway of fiddler to "127.0.0.1:8888" where burp listens, then fiddler works ok...but it's also too complicated.

 

thx for your reply...(may u have a try?)

Hi guys. 

I investigate responses from . And Fiddler is tool for this.

But now I need  logs from Fiddler for 2-5 days and compare responses.

Fiddler grabs a lot of memory during 1 day and may cause my PC out of memory.

Request:

Automate autosaving saz files 4 hours with time-date in saz name, clear capture dialog and do it in the loop each next 4 hours.

 

When the PDFView Inspector is installed (v1.1.0.3, whose public override int GetOrder() method returns 500), the Response Inspectors are rendered out of order, such that the Headers/Transformer inspectors are not at the front of the list.

 

 

Since more and more websites enforce you to use tls 1.2 (and don't support tls 1.0 any more), I suggest that the list of protocols is automatically extended with tls1.2 by a next fiddler update - or at least there should be a single-time question box with Yes-No-Cancel to extend it.

Also see reference at https://www.telerik.com/forums/some-https-sites-are-unaccessible-when-using-fiddler

Hi,

I'm developing an application with Angular using Windows Authentication.

I tend to have Fiddler running all the time as it provides the authentication (using the Fiddler Automatically Authenticate flag).

As I have it running continuously the request pane gets quite large and the memory footprint increases as a result.  This is fine, and just the nature of the beast.

Periodically I clear the request pane out with CTRL+X but I have to maximize the Fiddler window first.

It would be really helpful if there was an additional option to clear the request pane from the menu on the system tray icon (please see attached).

Many thanks, and keep up the good work.  Cracking tool.

Franz.

Decrypt not working on some sites

执行“bpu xxx”请求断点后，AutoTamperRequestBefore(Session oSession)方法里oSession.oFlags.ContainsKey("x-breakrequest")=false。

但是执行“bpa xxx”响应断点后，AutoTamperResponseBefore(Session oSession)方法里oSession.oFlags.ContainsKey("x-breakresponse")=true。

There are some Files, fiddler needs write privileges:

rm: cannot remove '/opt/fiddler/listeningProcess.txt': Permission denied
rm: cannot remove '/opt/fiddler/gsettings.txt': Permission denied
rm: cannot remove '/opt/fiddler/proxiesFromInterfaces.txt': Permission denied
...

If this file is stored with the exe file, it is not possible to install fiddler in /bin or /opt and run without root privileges.

I think it would be good to locate that file in the users home folder or in /tmp.

please add comments into a fiddler AutoResponder. And maybe hierarchy view for i can  create folders and create responses inside folders (for grouping). With group switch on|off.

 

 

I find myself applying the same filters again and again on each launch of Fiddler (I mean the filters listed below the list of requests).

I think it would be really great if you could allow the restoration of previously applied filters (e.g. by having a save/load filters option).

Also, allowing to filter out by "Request Method" would be great too.

Congratulations on this tool, by the way.

It is really great. :)

Hi I am using Progress Telerik Fiddler Web Debugger version v5.0.20182.28034 for .NET 4.5 and I am unable to capture Https service wherein I can easily capture the HTTP traffic. The application for which I am capturing traffic is an ASP Dot net Core web application having version ASP.NET and Web Tools 2017 version 15.9.1 Microsoft Visual studio Enterprise 2017. I am facing issues in capturing Https traffic in spite of installing the root certificate and changing the system proxy for each protocol (HTTP, HTTPS, FTP) settings to 127.0.0.1:8888. Kindly help me with this.