Picking the right UI/UX design agency is one of those decisions that can quietly make or break your product. Here's what to actually look at before you sign anything.

Start with the portfolio, but look past the visuals. Find case studies from early-stage products, MVPs, or companies that were operating under real constraints. If every project in their portfolio was a well-funded rebrand, they probably haven't dealt with the messy reality of startup timelines and limited budgets.

Next, ask about their UX process. A good agency has a real methodology: discovery, research, prototyping, testing. Push them on specifics. How do they run user research? How do they handle revisions? If they want to skip straight to visuals, that's a warning sign. Beautiful screens that don't solve real problems aren't worth much.

Communication matters more than most founders expect. Ask what tools they use to manage projects and how often you'll get updates. You shouldn't have to chase them for status reports. The agency should feel like part of your team, not a vendor you're waiting on.

Talk to their past clients directly. Not just the references they hand you, but anyone you can find. Ask whether they hit timelines, how they handled scope changes, and whether the final product matched what was promised. This is where you find out what working with them is actually like.

Pay attention to the questions they ask you. An agency worth hiring will want to understand your business model, your users, and your growth goals before they touch a design tool. If the first conversation is all about color palettes and branding, they're leading with aesthetics when they should be leading with strategy.

Finally, get a clear proposal. Itemized deliverables, defined scope, explicit pricing. Vague statements of work have a way of turning into billing disputes three months in. Clarity up front saves everyone time and money.