UI (User Interface) design is the visual craft - colour palette, typography, button styles, icon sets, spacing, and aesthetic consistency across every screen a user sees. UX (User Experience) design is the architectural and strategic craft - the navigation structure, user flows, information hierarchy, task completion logic, and whether users can achieve their goals without confusion or frustration. A product with beautiful UI but terrible UX looks impressive but frustrates users. Both are essential before any performance marketing or social media campaign drives traffic to the site - paid traffic landing on a confusing interface is wasted spend.