The Fiddler Web Debugger is now old enough to drink, but I still use it pretty much every day. Fiddler hasn’t aged entirely gracefully as platforms and standards have changed over the decades, but the tool is extensible enough that some of the shortcomings can be fixed by extensions and configuration changes. Last year, IContinue reading “Fiddler in 2025”
Tag Archives: Fiddler
Understanding SmartScreen and Network Protection
The vast majority of cyberthreats arrive via one of two related sources: That means that by combining network-level sensors and throttles with threat intelligence (about attacker sites), security software can block a huge percentage of threats. Protection Implementation On Windows systems, that source of network threat information is commonly called SmartScreen, and support for queryingContinue reading “Understanding SmartScreen and Network Protection”
Fiddler – My Mistakes
On a flight back from Redmond last week, I finally read Linus Torvalds’ 2002 memoir “Just For Fun.” I really enjoyed its picture of Linux (and Torvalds) early in its success, with different chapters varyingly swooning that Linux had 12 or 25 million users. But more than that, I enjoyed some of the “behind theContinue reading “Fiddler – My Mistakes”
Capturing Logs for Debugging SmartScreen
The Microsoft Edge browser makes use of a service called Microsoft Defender SmartScreen to help protect users from phishing websites and malicious downloads. The SmartScreen service integrates with a Microsoft threat intelligence service running in the cloud to quickly block discovered threats. As I explained last year, the SmartScreen service also helps reduce spurious securityContinue reading “Capturing Logs for Debugging SmartScreen”
Edge’s Super-Res Image Enhancement
One interesting feature that the Edge team is experimenting with this summer is called “SuperRes” or “Enhance Images.” This feature allows Microsoft Edge to use a Microsoft-built AI/ML service to enhance the quality of images shown within the browser. You can learn more about how the images are enhanced (and see some examples) in theContinue reading “Edge’s Super-Res Image Enhancement”
Extending Fiddler’s ImageView
Fiddler’s ImageView Inspector offers a lot of powerful functionality for inspecting images and discovering ways to shrink an image’s byte-weight without impacting its quality. Less well-known is the fact that the ImageView Inspector is very extensible, such that you can add new tools to it very simply. To do so, simply download any required executablesContinue reading “Extending Fiddler’s ImageView”
Analyzing Network Traffic Logs (NetLog json)
Previously, I’ve described how to capture a network traffic log from Microsoft Edge, Google Chrome, and applications based on Chromium or Electron. In this post, I aim to catalog some guidance for looking at these logs to help find the root cause of captured problems and otherwise make sense of the data collected. Last Update:Continue reading “Analyzing Network Traffic Logs (NetLog json)”
Capture Network Logs (NetLog) from Edge and Chrome (and Electron and WebView2)
Problems in accessing websites can often be found and fixed if the network traffic between the browser and the website is captured as the problem occurs and the resulting log file is shared with engineers. This short post explains how to capture such log files. Capturing Network Traffic Logs If someone asked you to readContinue reading “Capture Network Logs (NetLog) from Edge and Chrome (and Electron and WebView2)”
Firefox and Fiddler – Easier than Ever
In a world where software and systems seem to march inexorably toward complexity, I love it when things get simpler. Years ago, Firefox required non-obvious configuration changes to even send traffic to Fiddler. Eventually, Mozilla changed their default behavior on Windows to adopt the system’s proxy, meaning that Firefox would automatically use Fiddler when it was attached,Continue reading “Firefox and Fiddler – Easier than Ever”
Fiddler And LINQ
Since moving to Google at the beginning of 2016, I’ve gained some perspective about my work on Fiddler over the prior 12+ years. Mostly, I’m happy about what I accomplished, although I’m a bit awed about how much work I put into it, and how big my “little side project” turned out to be. It’sContinue reading “Fiddler And LINQ”