A jQuery developer designs and implements user-friendly web interfaces using jQuery, a JavaScript library. They create dynamic and interactive features on websites to enhance user experience. Their tasks include writing, testing, and debugging JavaScript and jQuery codes, optimizing web applications for maximum speed and scalability, and ensuring cross-browser compatibility. They also work closely with web designers and back-end developers, transforming static layout into responsive and interactive features. Additionally, they are responsible for maintaining and improving websites, fixing bugs, and making necessary updates. They must keep abreast of the latest jQuery developments and trends to implement cutting-edge features.