Is ReactJS a front-end or backend?

ReactJS is a popular open-source JavaScript library created by Facebook and employed for constructing user interfaces (UIs). It is used for developing single-page applications and mobile apps, as well as for creating complex UIs for web applications. ReactJS is written in JavaScript and follows the Model-View-Controller (MVC) architecture, which divides the application into three parts: the model (data), the view (user interface), and the controller (logic).

ReactJS is mainly employed for generating user interfaces. It provides developers with a library of components, which can be reused and combined to form complex UIs. ReactJS also allows developers to create custom components, which can be utilized to create interactive UIs. Also, ReactJS provides developers with a virtual DOM, which allows them to make efficient modifications to the user interface without needing to reload the page.

So, is ReactJS a Front-End or Backend technology? ReactJS is a front-end technology, meaning it mainly deals with the user interface of a website or application. While ReactJS can be used for creating complex user interfaces, it does not interact with the server or manage the backend logic of an application. For that, developers will need to use a backend technology such as Node.js or PHP.