Framer is a modern prototyping tool. It can help you to quickly build and test complex interactions and rich animations for both desktop and mobile. The basic idea is that you only need a few simple building blocks like images, animation and events to build and test complex interactions.

It is made for designers. It is simple but powerful. A good alternative to Flash, Quartz Composer or Keynote. It works great in desktop and mobile Safari or Chrome, and Offline too. It uses webkit css transforms to render on the GPU for smooth performance. Built in easy spring physics for iOS like animations.

Requirements: -
Demo: http://www.framerjs.com/
License: License Free