Telerik Fiddler, web debugging proxy

With Telerik Fiddler you can debug web browsing using a proxy that takes care of recording all the data exchanged between your computer and web pages through HTTP or HTTPS connections. It inspects all traffic, sets breakpoints, and is even capable of allowing manipulation of incoming and outgoing data.

It uses a powerful command system that can be extended using any .NET language. With Fiddler you can scrub traffic from any application that supports a proxy , including all browsers.

What does Fiddler offer?

You can use it with Internet Explorer and Microsoft Edge, Mozilla Firefox, Google Chrome, Safari, Opera and many other applications that connect the network with your computer. It also allows debugging on mobile devices that use Android or iOS, among other systems.

The program can be enriched with some extensions, which you can download from the website that supports it. It is a free app that works on the latest versions of Windows, macOS, and Linux.


Among the various functions that accompany this tool, the following should be distinguished:

  • Web debugging : Controls the flow of content, including cookies, headers, and cache directives, between most web browsers, on any operating system for computers and mobile devices, between the client and the server.
  • Performance tests : It is possible to check the total weight of the web page, enable caching and see the status of GZIP compression.
  • HTTP / HTTPS Proxy : Records and filters all the flow through the HTTP and HTTPS web protocols.
  • Web session manipulation : It is possible to set web session breakpoints, as well as set custom requests.
  • Security tests : You can perform security tests on web applications, decrypt HTTPS traffic, or modify requests.
  • Personalization : The program offers interesting customization options, with which it is possible to adapt it to the needs of each one.
  • All technologies : We have already noted that it supports most web browsers and operating systems. To this we must add support for almost all programming languages, including PHP and Java.

To consider

It is a customizable, free to try tool that enables web session manipulation, includes performance and security testing, is capable of recording HTTP and HTTPS traffic, and supports web debugging.


To get this application you have to access Fiddler .