I would like to know if there are any applications like fiddler but for mac OS X, as I need to debug some requests from web applications in Mac OS X. I used to do it with fiddler on Windows and would love to have this tool available on Mac as well.
There's the more general but perhaps not as helpful to you Wireshark.
One of the SO server sites might be better suited for your question. In fact, it's already been asked on SuperUser.