The relevance of responsive design in web applications lies in its ability to ensure optimal viewing experiences across a variety of devices, including desktops, tablets, and smartphones. Responsive design uses fluid grids, flexible images, and CSS media queries to adapt layouts based on the user’s screen size. This reduces the need for separate mobile sites and enhances user engagement. As more users access the web through mobile devices, responsive design becomes vital for improving accessibility and ensuring consistent, easy navigation regardless of the platform.