Every week, a startup founder asks us "do I need a UI designer or a UX designer?" — usually followed by "what's the difference, really?" If you hire the wrong one, you'll spend six months building something beautiful that nobody can figure out. Here's what each actually does.
The one-sentence answer
UX design is how it works. UI design is how it looks. UX is the architecture; UI is the paint job.
That distinction matters because the skills, the tools, and the deliverables are different. Most "UI/UX designers" you hire today are really UI designers who know enough about UX to ask the right questions. That's fine for a landing page. It's not enough for a product.
What a UX designer actually does
- User research: interviews, surveys, analytics review, competitive analysis
- Information architecture: how content is organized and labeled
- User flows: the path a user takes to accomplish a task
- Wireframes: low-fidelity layouts focused on structure, not visuals
- Prototyping: interactive mockups used for testing
- Usability testing: watching real users attempt tasks and noting where they fail
A UX designer's deliverable is a tested, validated flow. Their tools are mostly non-visual: spreadsheets, interview transcripts, journey maps, low-fidelity wireframes in Figma or paper.
What a UI designer actually does
- Visual design system: typography, color, spacing, iconography
- Component design: buttons, inputs, cards, modals, tables
- Page-level composition: how a wireframe becomes a designed screen
- Motion design: how things move and respond
- Responsive design: how the design adapts across screen sizes
- Accessibility: color contrast, focus states, screen reader behavior
A UI designer's deliverable is a designed, production-ready interface. Their tools are visual: Figma, Sketch, After Effects for motion, the component library your engineers use.
Where it gets confusing
Most people doing "UI/UX" today are really doing UI with some UX thinking baked in. That's normal and works for small projects. The breakdown shows up at scale:
- Small sites (< 10 pages): one designer can do both. UI is 80% of the work.
- Mid-size products (10-50 screens): split the roles. UX does research and IA, UI does the visual system.
- Large products (50+ screens, multiple flows): you need both, plus a design system owner.
How to tell which one you actually need
Ask one question: do you know what to build?
- If the answer is "yes, I just need it to look great" → you need a UI designer.
- If the answer is "I think I know, but I haven't tested it" → you need a UX designer first, then a UI designer.
- If the answer is "I have no idea what to build" → you need a product strategist before you need either.
What to look for when hiring
For a UX designer: ask them to walk you through a recent research project. The right answer involves real users, real interviews, and surprising findings. The wrong answer is "I do user flows in Figma."
For a UI designer: ask to see a design system they built or maintained. The right answer involves tokens, variants, accessibility considerations. The wrong answer is "here are some screenshots of landing pages I made."