ReactJS is an open-source JavaScript library that aims to simplify the complex process of building interactive UIs. Known for its speed, flexibility, and strong online community, ReactJS is the most popular JavaScript library. Its main advantage is its component-based approach. In React, you can develop applications by creating reusable components. These components are like Lego blocks that you assemble to form a complete UI. Currently, ReactJS is widely used to create dynamic UIs. Its primary use is in developing SPAs (single-page applications). In this article, we will show you how to install ReactJS on Ubuntu 26.04.