One of the great things about being a web developer today is the large amount of tools available to help troubleshoot and optimize applications. Over the past number of years, my team and I have shared information about these tools through the Canadian Developer Connection blog and events like the realDEVELOPMENT_07 tour. Some examples include FirebugYSlowYUI Compressor, the Internet Explorer Developer Toolbar and others. In fact, I wrote about a great episode of Hanselminutes where Jeff Atwood provided the audience with a list of some tools that he uses.

Of all the tools available for web developers, there’s one that I particularly like and that tool is Fiddler:

Fiddler is a freeware utility written by Eric Lawrence that logs all of the HTTP(S) traffic occurring on your machine. Recently, Eric delivered a presentation at Microsoft PDC 2009 entitled, "Become a Web Debugging Virtuoso with Fiddler", which you download from here. For the uninitiated, this session provides a great primer to Fiddler. Highly recommended.

I like Fiddler a lot because it gives me an ability to watch all HTTP(S) traffic that occurs on my machine and inspect the underlying aspects of this traffic on a request-by-request basis. This is important when building a web application where you want to have a clear understanding of what it's doing underneath the user interface.

Another aspect of Fiddler that I like is the ability to get a better sense of the HTTP(S) traffic itself. For example, with Fiddler I can examine the HTTP headers (including cookies). This is useful when you want to see how your web server utilizes caching via content expiration or compression via GZIP encoding. These aspects turn out to be quite important, especially when trying to reduce the frequency and size of your client requests.

Extensibility in the form of add-ons is the probably the best feature of Fiddler. With this capability, developers are free to extend the functionality of Fiddler to provide more meaningful information around the HTTP(S) traffic that occurs on a machine. There are many add-ons available for Fiddler. For a full listing, check out the extensions page here.

In conclusion, many tools exist for web developers. However, if there's one tool that's an absolute must, it's Fiddler. Download it today!