15 questions to ask a UI/UX design agency before you sign
The 15 questions that separate a good UI/UX design agency from a good pitch, with what a strong answer sounds like and the red flags that mean walk away.
- Ask to see a live product on a phone, not a portfolio shot. Shipped work is the only proof that counts.
- Get the names, roles and days per week of the people who will do the work, written into the proposal.
- Ask what the price includes and how scope changes are handled before you see a number.
- Send the same 15 questions to three to five agencies and score how specific the answers were.
Ask to see a live product they designed, who will do the work, how they research, what the price includes, and what happens after launch. Good agencies answer with specifics and examples. Vague answers, a price before any questions, or pressure to sign fast are the signs to walk away.
You will spend weeks with whichever agency you pick, and a large share of your budget. These 15 questions take about 30 minutes on a first call. Send the same list to every agency on your shortlist, so you can compare like for like.
Each question comes with what a good answer sounds like and a red flag. Use them as a guide, not a script.
Work and proof
The first group tests whether the agency has done work like yours and can show it.
1. Can you show me a live product you designed that is similar to ours?
Screens in a portfolio show taste. A live product shows whether the design survived engineering, legal review and real users. This is the single most useful question on the list, so ask it first.
Listen for an agency that opens the product on a phone during the call and walks you through one flow. The best ones also tell you what they would change now. That shows they still think about the work after the invoice is paid.
2. What was the result for the client?
Agencies that measure outcomes design toward them. Agencies that do not measure anything design toward the screenshot.
A good answer names one specific change and how it was measured: fewer support tickets, a higher activation rate, a shorter checkout.
The red flag is a result that sounds like a testimonial. “The client loved it” tells you about the relationship, and nothing about the product.
3. What would you do differently on that project now?
This tests honesty and whether the agency learns from its own work.
A good answer names a real mistake and the change it caused in their process. Perhaps they skipped usability testing to hit a deadline and now protect that time. Perhaps they handed over a component library that the client’s engineers could not use.
“Nothing, it went perfectly” is the red flag. Either they are not being straight with you or they have not looked closely.
4. Have you worked in our industry, and what did you learn?
Industry knowledge saves weeks, especially in regulated spaces like fintech, health or insurance. An agency that already knows what compliance review does to a design timeline will plan for it. One that does not will discover it halfway through.
A good answer names specific constraints: identity checks that have to sit in a particular order, accessibility rules that apply by law, a legal team that signs off every screen. You want the agency to already know the things that would surprise a newcomer.
“Good design works in any industry” is the red flag. It is true in a general way and useless in a specific one.
5. Can we speak to a client from the last 12 months?
A recent reference tells you about the team you will get now. A reference from four years ago tells you about people who may have left.
Ask for an introduction to a named client, ideally one whose project went through a rough patch. How an agency handles a difficult month tells you more than how it handles an easy one.
Written testimonials only, or references from years ago, are the red flag.
Process and people
The second group tests who will do the work and how. The people in the pitch are often senior partners. The people on your project are often someone else.
6. Who exactly will work on our project?
You are hiring individuals, not a logo. Ask for names, roles and links to their work, including who leads day to day and who you will message when something is wrong.
7. How much of their week is ours?
A designer split across five clients moves slowly on all of them. This question catches the gap between a strong team on paper and a strong team in practice.
A good answer gives a number of days per week per person, and the agency is willing to write it into the proposal.
“As needed” is the red flag. It means the agency will decide week by week, based on which client is shouting loudest.
8. What research will you do before you design screens?
Research is where agencies find the problems you did not know you had. Skipping it lowers the quote and raises the risk of designing the wrong product beautifully.
A good answer names methods, numbers and timing: eight user interviews in the first two weeks, a review of your analytics, a usability test of the current product. The agency should also say what it does if research contradicts the brief.
One kick-off workshop counted as research is the red flag. A workshop captures what your team already believes. Research finds out what your users actually do.
9. How do you test designs with real users?
Testing a prototype costs a few days. Fixing the same problem after launch costs an engineering sprint and some of your users’ patience.
Listen for prototype tests with your actual users, a sample size, and a plan for what happens when a test fails.
Internal reviews only is the red flag. The agency’s own designers are the people least able to see what confuses a stranger.
10. How do you hand designs to our engineers?
Handoff is where good designs most often get lost. A beautiful Figma file with no documented states turns into guesswork during build, and the guesses rarely match the design.
A good answer includes a component library, documented states for every element (empty, loading, error, edge cases), and time set aside during build to answer engineering questions. Ask whether that support time is in the price or billed separately.
11. What does accessibility mean in your process?
Accessibility affects a large share of your users, and in many markets it is a legal requirement. For a financial or public-facing product it can be a condition of launch.
A good answer names a standard, usually WCAG 2.2 AA, and describes the checks built into design reviews: colour contrast, focus order, text size, keyboard paths. The agency should be able to show a product it designed that passed an audit.
“We can add that at the end” is the red flag. Accessibility added at the end means screens redesigned at the end, at your cost.
Money and terms
The third group is where most budget surprises start.
12. What is in the price, and what would cost extra?
Most overruns come from things nobody listed. Two rounds of revision or four. Research included or priced separately. Design support during build or a new invoice when engineering has questions.
Ask for a written list of deliverables, the number of revision rounds, and a list of what sits outside scope. Compare that list across agencies. A higher price with more included is often the cheaper option.
A single number with no breakdown is the red flag. If the agency cannot say what the number buys, you cannot compare it with anyone else’s.
13. How do you handle a change in scope halfway through?
Scope always changes. You will learn things during research. Your business will shift. The question is how the agency handles that, and whether you find out the cost before or after the work is done.
14. What happens after launch?
Your product keeps changing after the agency leaves. You need a clear path for small changes, a retainer option if you want one, and files your own team can maintain.
A good answer covers all three: a support option with a price, a handover that includes source files and the component library, and no dependence on tools or licences only the agency holds.
Files only the agency can work with is the red flag. It turns every future change into a new project with one possible supplier.
15. What would make you turn this project down?
Agencies that know their limits are easier to trust.
A good answer is specific: a budget below a certain band, a timeline shorter than their process allows, or a product type they have not worked on.
“We’d never turn you down” is the red flag. An agency that takes every project is an agency with capacity problems waiting to happen.
How to run the calls
Write a one-page brief first, so every agency answers the same project. Our guide on how to write a UX design brief agencies can actually quote has a template.
Send the brief and these questions to three to five agencies. Fewer gives you nothing to compare. More turns into weeks of calls and a decision made from fatigue. Start your shortlist with our list of 20 leading UI/UX design agencies, which shows budget tier, hourly rate and location side by side, and check what your budget buys in the UX design cost guide.
Give every agency the same decision date. Then score each call on three things:
- How specific the answers were. Named people, named methods, named numbers.
- Whether the agency asked good questions back. The best ones interview you too.
- Whether their examples match your project in type, stage and industry.
The agency with the best portfolio is often not the one that answered best. Hire the one that answered best.
If you would rather skip the calls, send us your brief and a person will introduce three agencies that fit, within 48 hours. It is free for buyers.
Frequently asked questions
How long should a first call with an agency take?
Thirty to forty-five minutes is enough for these 15 questions. If the agency runs the call as a sales presentation and you reach the end without asking anything, book a second call or drop them.
Should I share my budget before the call?
Yes, as a band. Agencies will not lower their rates when they hear a number. They will shape the scope to fit it. Without a band, every proposal is built on a guess, and the guesses will not match. Our cost guide explains the four bands most agency work falls into.
What if an agency answers well but costs more than the others?
Compare what each price includes before you compare the totals. An agency that includes research, testing and build support often costs less overall than one that bills each of those as an extra. If the more expensive agency is still more expensive after that, decide whether the difference buys lower risk on your particular project.