A commonly used programming framework for developing server-side applications is Node.js. Node.js enables developers to build scalable and efficient web applications using JavaScript on the server side. With its non-blocking architecture, it can handle multiple connections simultaneously, making it suitable for real-time applications such as chat services or collaborative tools. Node.js also boasts a rich ecosystem of libraries and frameworks, which accelerates development and enhances functionality. Its popularity stems from its ability to streamline development processes and allow for the use of a single programming language across both client and server sides.