Brothers In Code

...a serious misallocation of .net resources

Fiddler Rocks for Debugging Web Applications!

Every once in a while you run across a free tool that makes tough problems trivial in a clean and simple way.  I've used a handful of http debugging proxies, including those that aren't cheap, let alone free, and none of them hold a candle to Fiddler ( 

More than once I've been stuck with some cryptic browser problem that just wasn't a first-page google fix.  And of course the problem is often different depending on the browser version, if it was over an https connection, etc.  I recently had a problem where a dynamic pdf just would not open in IE when requested over ssl from IIS 7.  The browser would just open a blank page so I had no error message to search on.  I decided to fire up fiddler and compare the http with the https response.  Sure enough, IIS was appending some no-cache headers to the response. 

And that was just one issue.  I've used Fiddler to:

  • Inject CSS in order to test a style on a site I didn't host.
  • Redirect traffic from mobile devices to my development server so I could avoid using my local IIS server.
  • To see xml exchanged between Oracle and a SharePoint webservice. 

Bottom line, if you anything with the web or the http protocol, download Fiddler today.