CodePen - A front end web development playground.
Parse - Build applications faster with object and file storage, user authentication, push notifications, dashboard and more out of the box.
JSFiddle - Test your JavaScript, CSS, HTML or CoffeeScript online with JSFiddle code editor.
Firebase - Firebase is a cloud service designed to power real-time, collaborative applications for mobile and web.
JS Bin - Sample of the bin:
AnyPresence - AnyPresence is an Enterprise Backend as a Service for mobile app development and API augmentation.