React Native is a JavaScript framework which allows you to build mobile apps with a natively rendering UI for iOS and Android. React Native inherits the best features of web development like high speed, responsiveness, and agility. It uses the same design as React which allows developers to compose a rich mobile UI from declarative components. 

With React Native, you can provide your users with a native app along with effectual processing and a great user experience.

Some of the benefits of using React Native in your app are 

• Faster Development: No need to wait for re-compiling the entire app during development. Go ahead and make changes, the app reloads instantly. This results in a much faster development cycle.
• Reusable code: Same codebase can be used for multiple platforms. This saves development time and money. As much as 90% of the code can be reused between Android and iOS applications.
• Declarative style: React Native follows a declarative style of programming. This means UI is a function of state and properties which reduces the possibility of bugs drastically. React Native uses JSX, a syntax extension to JavaScript, which helps coupling UI with business logic of your app.
• Live updates: With React Native, developers can push the updates to users’ devices on the fly without having to go through the app store update cycle. This has been made possible due to an extensive use of Javascript.
• Great for web developers : Majority of codebase of a React Native app is JavaScript. If you’re good with JavaScript, React Native will be easy to pick-up, allowing most front-end web developers to be a mobile developer. All you need to know is JavaScript, platform APIs, some native UI elements, and any other platform-specific design patterns and you’re set.