What Is the Difference Between UI and UX Design & Why It Matters

UX is the journey; UI is the surface. UX design decides what the product does and in what order; UI design decides how each step looks and feels.

Two roles, one goal

UX research, information architecture and flows answer "can people get this done?" UI typography, colour, spacing and components answer "does it feel clear and trustworthy while they do?" Confuse them and you get beautiful screens nobody can use, or usable screens nobody wants to.

Why it matters

The best teams keep both honest. Structure first, surface second — but always together.