Fiddler is freeware and can debug traffic from virtually any application, including Internet Explorer, Mozilla Firefox, Opera, and thousands more.
Fiddler 2 has replaced Fiddler 1.x. Fiddler 2 supports debugging HTTPS traffic, a richer extensibility model, and can by installed side-by-side with Fiddler 1.x if desired.
Requires: Microsoft .NET Framework 4.0.
"Superb Web Development Tool"
Reviewer: -kcalvert Review Date: 2009-05-03
Average Rating (13 Votes )
Other Thoughts: I have used this tool at work for monitoring HTTP traffic and debugging web sites. The information it provides is excellent. It provides multiple views of data and allows traffic modification. It is also extensible through scripting. Highly recommended for serious web developers.