An alpha build of Fiddler for Mono is available and enables you to run Fiddler directly on the Mac. Unfortunately Mac’s Mono WinForms framework isn’t very robust and frequently crashes due to bugs not present in the Linux Mono framework or the Microsoft .NET Framework on Windows. Therefore, Mac users often get the best results by running Fiddler inside a virtual machine running either Linux or Windows.
Until a new build of Fiddler for the Mac (based on a more mature UI Framework) is available, I hope these instructions enable you to use Fiddler effectively on your Mac!
Eric Lawrence (@ericlaw) has built websites and web client software since the mid-1990s. After over a decade of working on the web for Microsoft, Eric joined Telerik in October 2012 to enhance the Fiddler Web Debugger on a full-time basis. With his recent move to Austin, Texas, Eric has now lived in the American South, North, West, and East.