Node.js is an open source, JavaScript-based runtime environment that enables the execution of JavaScript code on the server-side. It uses an event-driven, non-blocking I/O model that makes it lightweight and efficient, and is becoming increasingly popular in the development community due to its scalability, speed, and reliability.
In order to make building applications faster and easier, developers are turning to frameworks. A framework is a set of tools and libraries that provide structure and guidance when building applications, and there are several frameworks available for Node.js.
Express.js is a web application framework for Node.js that is designed for building web applications and APIs. It is known for its robustness, scalability, and speed and is open source and free to use. Koa.js is a newer Node.js framework that is minimalistic and provides a simple and clean API for developers. Mojito is a full-stack web application framework for Node.js that is designed to be highly extensible and to provide a complete development environment for building web applications. Finally, Meteor is a full-stack JavaScript framework for building real-time web applications.