Is React js free

Why we use React

React is now widely used for modern web applications / projects, from small and simple (e.g. single page applications) to large and complex. It's very flexible and can be used for UI projects of any size and platform, including mobile, web, and desktop development. Many world-famous companies, such as Instagram and Airbnb, therefore rely on React for their products.

The features and benefits of React

Virtual DOM

Performance is the biggest challenge in today's dynamic web applications. In order to enable dynamic websites, a DOM (Document Object Model) is built in the browser, which saves all elements, no matter how small, in a tree structure in order to then carry out operations such as the calculation of positions or properties such as color, size, etc. If the DOM or some of its properties are to be changed, the DOM must be recalculated. For this purpose, jQuery is typically used, which carries out the operations via the browser DOM. Since the elements can influence each other in a wide variety of ways, these changes or calculations are quite time-consuming.

Virtual DOM solves this problem in React: By storing the DOM in memory and only updating it selectively, it can be changed very quickly and the number of updates in the browser is minimized.


Components allow you to break your user interface into independent, reusable parts and view each part in isolation. The components are JavaScript functions or classes (since ES6) with a render method.

One way data flow

React only transmits the data in one direction, towards the components. This simplifies debugging.


A fundamental concept of React is JSX. JSX is an extension of the JavaScript programming language and enables HTML-like elements to be used seamlessly in JavaScript. With JSX, React is simply connected to the display (view layer). The idea behind JSX is no longer to separate according to technology, but according to responsibility. This concept is called Separation of Concerns (SoC). Since a component no longer has to be combined from two entities, JSX helps to write self-contained components that are themselves very easy to reuse.

Advantages of React for Development


React has a very steep learning curve because it is very easy to build components with. A component in React is little more than a JavaScript class that contains all of the logic to represent the component. You don't even have to learn a template language to write a component, because the UI part of a component is written in React using JavaScript. JSX improves readability, especially by making it easier to write DOM elements.

Scalability and flexibility

The core of React are components and their composition for an application. The components are divided into classes that can be easily expanded and transferred. This allows scalable and flexible applications to be developed. In addition, the component status can be checked and changed at any time using the React API.

Simplified development complexity and reusability

Another big advantage of React is the JSX syntax extension, which offers excellent reusability. The standard mechanics at React suggest using standardized inline styles described with JavaScript objects. JSX combines HTML and CSS in one JavaScript code and frees you from the pain of having to insert links to other files via attributes. Each component can be freely defined anywhere in the project by assigning it a certain unique status.

Active community and sufficient reusable components

React with its ecosystem is a kind of flexible framework. You can choose libraries yourself and add them to the core of the application.