Ember.js is an open-source JavaScript web framework, based on the Model–view–viewmodel (MVVM) pattern. It allows developers to create scalable single-page web applications. Developed by emberjs
License: Open Source
Polymer is focused on web components and is lightweight, making it easy for beginners to create reusable components, while Ember.js offers a more complete framework with strong conventions and a rich ecosystem, but can be more complex to learn.