Fiddler and Silverlight Cross-Domain Requests

I’ve recently heard from a number of Silverlight developers who report that certain cross-domain web service requests from their applications work properly with Fiddler running, but fail when Fiddler is not active. Using lower-level tools like NetMon or by watching server logs, the developers note that their applications aren’t even issuing requests for the cross-domain…


Fiddler and Channel-Binding-Tokens

Note: Please see this post for an update. Some users of Fiddler who have HTTPS Decryption enabled have found that some of their internal HTTPS sites that used to work properly with Fiddler now endlessly prompt for credentials while Fiddler is running. Even typing the correct credentials into the authentication prompt won’t fix the problem….


Fiddler and the Windows Phone 7 Emulator

Note: This post is part of a larger set on using Fiddler with Windows Phone 7. This post covers the Windows Phone Emulator only. Recently, some developers have asked me why Fiddler no longer works with the Windows Phone 7 emulator. Fiddler properly captured traffic from the CTP version of the emulator, but not from…


FiddlerCore Update

FiddlerCore version is now available for download. The primary change in this update is that the installation package now includes FiddlerCore4.dll, a version of the assembly compiled to run on the .NET4.0 CLR. I expect to maintain versions of this assembly for both the v2 and v4 CLRs for the foreseeable future. Beyond the…


Automatic Authentication with the Request Builder

The Request Builder feature in recent versions of Fiddler includes a number of enhancements, including the ability to follow HTTP redirections, and to automatically authenticate (using the current user’s credentials) to servers that demand authentication using the NTLM or Negotiate (NTLM/Negotiate) challenge-response protocols. Following redirections is simple enough, but properly constructing a response to a…


New Features in Fiddler Beta

New features and fixes in the Beta. The Find Sessions feature (CTRL+F) now supports searching with regular expressions. Enhanced the “Compare Sessions” feature on the context menu (set fiddler.differ.ultradiff = “False” if you don’t like it) Use a preference to persist the Scaling Mode preference in the Image Inspector Fix bug whereby the URL https://something/http://something would be…


New Features in FiddlerCore

Version of the FiddlerCore .NET class library has been released. This new version includes a number of new features that make FiddlerCore more useful for a variety of traffic monitoring and capture scenarios. With the exception of the final improvement (Server Read Callback), all of these improvements are also available to extensions running inside…


FiddlerCap Now in Six Languages

The FiddlerCap Web Traffic Recorder allows non-technical end-users to collect Web Traffic captures, and send those captures to a debugging buddy for analysis. I recently updated FiddlerCap and it can now render in any of six languages: English, Spanish, French, Japanese, Russian, and Portuguese. The product UI was translated by members of the Fiddler community,…


Fiddler’s New Import and Export Architecture

All versions of Fiddler support a rich extensibility model that enables developers to enhance Fiddler with new functionality useful for traffic inspection, analysis, and sharing. However, writing extensions that import traffic captured by other tools was difficult, and extensions that offered traffic export often extended the UI in confusing ways or failed to implement basic…


Capturing (and changing) a Web Site with Fiddler

Often, the IE team will encounter a problem in a complicated production website, and will need to “reduce the repro” in order to determine the root cause of a given bug. This is made more complicated by the fact that sometimes the live website will change under us and we may lose the repro before the…