Fiddler

Fiddler 5.0

Fiddler is a Web Debugging Proxy which logs all HTTP(S) traffic between your computer and the Internet.

Download options:
Freeware
Windows/macOS
1.2 MB
72,492
4.2 194 votes

Fiddler allows you to inspect traffic, set breakpoints, and "fiddle" with incoming or outgoing data. Fiddler includes a powerful event-based scripting subsystem, and can be extended using any .NET language.

Fiddler is freeware and can debug traffic from virtually any application that supports a proxy, including Internet Explorer, Google Chrome, Apple Safari, Mozilla Firefox, Opera, and thousands more. You can also debug traffic from popular devices like Windows Phone, iPod/iPad, and others.

Web Session Manipulation

Edit web sessions easily:just set a breakpoint to pause the processing of the session and permit alteration of the request/response. Compose your own HTTP requests and run them through Fiddler.

Performance Testing

Fiddler lets you see the “total page weight,” HTTP caching and compression at a glance. Isolate performance bottlenecks with rules such as “Flag any uncompressed responses larger than 25kb.”

Customizable Free Tool

Benefit from a rich extensibility model, ranging from simple FiddlerScript to powerful extensions which can be developed using any .NET language.
See full list of ready-made add-ons.

Security Testing

Decrypt HTTPS traffic and display and modify web application requests using a man-in-the-middle decryption technique. Configure Fiddler to decrypt all traffic, or only specific sessions.

 HTTP/HTTPS Traffic Recording

Use Fiddler to log all HTTP(S) traffic between your computer and the Internet. Debug traffic from virtually any application that supports a proxy (IE, Chrome, Safari, Firefox, Opera and more).

Web Debugging

Debug traffic from PC, Mac or Linux systems and mobile (iOS and Android) devices. Ensure the proper cookies, headers and cache directives are transferred between the client and server. Supports any framework, including .NET, Java, Ruby, etc.

What's New:

  • Added download link for macOS beta version
  • Add Packet Capture Import
  • Enhanced Composer
  • Enhanced AutoResponder
  • Enhanced Protocol Violation detection
  • Improved WebView
  • Add registry-fallback to EnableLoopback