The technology that supports enhanced user interactivity in web applications is primarily powered by JavaScript and related frameworks such as React or Vue.js. These technologies enable dynamic content updates without requiring full page reloads, creating a more fluid user experience. Behind the scenes, they interact with APIs to fetch data and respond to user actions in real-time. Features like drag-and-drop functionality, animations, and responsive design are facilitated by these technologies, allowing developers to build engaging and interactive web applications that can adjust to various devices and user inputs.