Over the years, we have received numerous requests from our user community to provide a Fiddler build for OS X. So we have ported the latest version of Fiddler to the Mono Framework which in turn supports OS X—and you can grab the beta bits today.
Many years ago, debugging a JavaScript code base was all about console.log() calls sprinkled in one or more functions under investigation. Sometimes you'd realize that the problem was not in those fun...