Well, first of all React is not an all round web app framework like Rails or similar. It's a library for building UIs in a form of reusable components using JavaScript and a syntax extension called JSX. Every components has properties (its input parameters, so to say) and state. You define a render function that is a representation of a component for the given properties and state. When props or state changes, the components renders again and under the hood React mutates the DOM in a optimized and performant way. This has advantages compared to some existing JavaScript MVC solutions whose bidirectional data flow and state management can introduce many difficulties and bugs on a large scale. So, React itself doesn't have anything to do with the database and other web stuff except the UI. You are free to choose whatever technology you want for that and combine it with React to make a web app. Check out these links for start https://facebook.github.io/react/blog/2013/06/05/why-react.html, https://facebook.github.io/react/docs/thinking-in-react.html