React Native has been around for about 4 years. React Native is a framework. It can be used for Android and build cross-platform apps. React Native comes with everything whereas ReactJs needs webpack so you don’t need to install anything. Also it is very easy to start a project with React Native, you only have to run a line in the terminal and its ready to go. React Native components you will have to create stylesheets in javascript.ReactJS can be run on a server and supports front-end and web. It can be used to make user interfaces and web applications. 

ReactJS is a javascript library You have to choose a bundler like webpack. Facebook developed ReactJs to be almost like writing your JavaScript inside of your HTML/XML. The capital letter tags which are custom component is the hallmark of ReactJs. React is used for web development. You can use reuse code component. Its virtual DOM is faster than the conventional full refresh model. It improves debugging speed.