LiveReload - LiveReload 2 proudly presents… The Web Developer Wonderland. (a happy land where browsers don't need a Refresh button). CSS edits and image changes apply live. CoffeeScript, SASS, LESS and others just work.
Charles - HTTP proxy / HTTP monitor / Reverse Proxy
Browsersync - Browsersync makes your tweaking and testing faster by synchronising file changes and interactions...
Surge for Mac - Advanced Web Debugging Proxy for Mac & iOS
CodeKit - CodeKit allows you to optimize the performance of your website by automatically and efficiently compiling a variety of popular languages.
Weer - A HTTP protocol debugger with Chrome DevTools frontend interface