CodeKit - CodeKit allows you to optimize the performance of your website by automatically and efficiently compiling a variety of popular languages.
SASS Compiler - Generate CSS code from sass source using SASS Compiler. Beautify CSS if necessary.
Fire.app - Fire.app is a menu bar only app for dead easy HTML prototyping.
LESS Compiler - LESS Compiler makes formatted CSS styles from less source.
Prepros - Compile Less, Sass, Scss, Stylus, Jade, Coffeescript, Haml and Markdown with live browser refresh.
JSONFormatter.org - Online JSON Formatter and JSON Validator will format JSON data, and helps to validate, convert JSON to XML, JSON to CSV. Save and Share JSON