Introducing Fiddler 4


A couple of days ago at I wrote about some of the new web debugging features in Google Chrome. I also mentioned the existence of a program which offers similar features for all browsers, and promised to write about it some more. So here we go.

Fiddler, recently updated to version 4, is technically known as a web debugging proxy. You'll be familiar with proxy servers if you've ever employed one to allow you to access web sites that are based in countries other than your own. A proxy is something which fetches a web page on your behalf, and then passes it back to your browser. If the proxy is based in a country other than your own, it can fool the server it's retrieving data from. Or in the case of Fiddler, if the proxy is based in your own PC, it can analyze the data returned from the server and then present its detailed results to you in addition to the actual web page you requested.

For example, access a typical web page nowadays and, even though it only contains a few KB of text, the total amount of internet traffic generated is likely to exceed 2 MB (that's 1000 times more, or an overhead of 100,000%). That's because your browser will probably need to connect to dozens of additional sites in order to load tracking information, cookies, images, and so on. With Fiddler, you can see all that data, and learn about just what's involved in making up a web page in today's world.

Fiddler is free and is where you need to go in order to download it. The download is around 1 MB and the program is malware-free according to VirusTotal and Web of Trust.

Whether you simply want to learn more about how the web works, or you are a web professional, Fiddler is one of those tools that you really need to know about. And the level of detail it can reveal is fascinating.

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Supposedly it works on Linux, using Mono instead of Net. Haven't tried.

How about an article on website debugging tools, Robert? For example Rex Swain's HTTP Viewer (excellent for viewing the important basic stuff), Wire Shark, etc.

Thanks for a good tip, Robert.

You'll need to know your .NET version before you download the app, so grab that first before you go to the download site (.NET2 or .NET4).