Polymer and React are both JavaScript libraries/frameworks used for building web applications, but they have some key differences.
Polymer is a library developed by Google that focuses on creating reusable web components using a set of standard web technologies. It emphasizes encapsulation and modular development.
On the other hand, React is a JavaScript library developed by Facebook that focuses on building user interfaces. It utilizes a component-based architecture and a virtual DOM for efficient updates and rendering.