UX and UI design are critical in e-commerce. A user-friendly UI enhances navigation, conversions, and satisfaction with intuitive interfaces complementing aesthetics reduces cognitive load on a user. Responsive design ensures accessibility across devices. In our study, we assessed cognitive load on an e-commerce site through usability testing on two ecommerce websites that are Amazon and Aliexpress, using heuristics questionnaires as post-task surveys and recorded the users click after completion of each task. We provided recommendations based on the results to enhance website design and minimize cognitive load.