What is polymer
Polymer is a framework for creating web components. Polymer is different than other web frameworks in that it only exists while browsers catch up on implementing the web components specification(which hasn’t been finalized).
Polymer doesn’t do much in helping you create single page apps. It doesn’t have a router, tools for internationalization or a nice abstraction for XMLHttpRequest. The way you build apps using polymer is by creating components that help you do those things.