Fiddler Classic | No Ads

While Fiddler Classic is the original Windows-only powerhouse, Telerik also offers Fiddler Everywhere . Fiddler Classic Fiddler Everywhere Windows Only Windows, macOS, Linux Cost Free for everyone Subscription-based UI Traditional, complex Modern, intuitive Collaboration Manual file sharing Built-in cloud sharing Getting Started

Fiddler Classic acts as a "man-in-the-middle" proxy. When enabled, it captures every request sent by your browser or applications and the corresponding responses from the server. fiddler classic

: Get the installer from the official Telerik page. : Get the installer from the official Telerik page

Simulating server errors (like 500 or 404) to see how your UI handles them. One of the most used features, the AutoResponder,

: Use the "Filters" tab on the right to narrow down your view to a specific host (e.g., *.yourdomain.com ).

One of the most used features, the AutoResponder, lets you serve local files instead of live server responses. This is invaluable for:

For advanced users, FiddlerScript offers near-infinite flexibility. By editing the CustomRules.js file, you can write C#-like scripts to automate traffic handling. For example, you can write a script to automatically add a specific header to every request or log specific session data to a file. Traffic Inspection & Filtering