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16 Feb 2027
How to check a design agency before you sign: reviews, references and results
Check a design agency like an investor: verified reviews, client calls, who does the work, real results, returning clients and contract basics.
Short answer
Treat it like due diligence, not a first date. Read verified reviews on an independent platform, call at least one past client yourself, ask who will actually do the work, look for results rather than pretty screens, find out how many clients come back, and read the contract for IP and a clean exit.
You’ve had three calls. Everyone was lovely. One studio had a dog wander into frame, which felt like a good sign. Another had a deck so polished you briefly considered rebranding yourself.
Here’s the catch: everything you saw in those calls was chosen by the agency. A portfolio is a trailer, cut by the people who made the film. You wouldn’t back a startup on its trailer, so don’t hand over your brand, your product and six months of runway for one either.
And the shortlist often turns up before you’ve spoken to anyone. In G2’s 2025 Buyer Behavior Report, a survey of 1,100 B2B software decision-makers, AI chatbots were the top source shaping vendor shortlists at 17.1%, just ahead of review sites at 15.1%. Gartner found that 61% of B2B buyers would rather skip the sales rep altogether. So the checking is down to you. Good news: it takes an afternoon.
At Dtail Studio, a Barcelona design studio working with HealthTech and renewable energy startups, we get vetted a lot. This is what we’d check if we were sitting where you are.
Where should you look for reviews of a design agency?
Somewhere the agency can’t edit. Homepage testimonials are a greatest-hits album, compiled by the band. An independent platform is harder to fake and easier to compare.
For design studios that usually means Clutch. Its methodology page says a human editor checks every review before it goes live, and reviews where the client’s identity and business relationship are confirmed get a Verified badge. Look for the badge, then ignore the stars and read the stories: what the project was, how big it was, and what went wrong. A review with one small complaint in it is worth three that just say “amazing”.
A wall of perfect scores with no detail deserves a raised eyebrow. Research for the UK Department for Business and Trade estimated that 11% to 15% of reviews in three common product categories were fake. Those were products, not agencies, but people are people. In the US, the FTC now bans fake reviews and testimonials, AI-written ones included.
Why should you speak to a past client yourself?
Because a review tells you how the project ended, and a call tells you how it felt in month three. Ask for one or two clients you can phone, ideally with a project like yours in size and stage.
Five questions are plenty:
What did they promise, and what did they deliver?
Who did the work day to day? Were they the people from the pitch?
What went wrong, and how did they handle it?
Did the work still hold up six months later?
Would you hire them again?
Only the last one really counts. Listen to the pause before the answer. A long pause is an answer.
A studio that can’t find a single client to put you in touch with is telling you something. So is one whose only reference wrapped up in 2019.
Who will actually do the work?
Ask for names, because the people in the pitch aren’t always the people in the files. Big agencies sometimes sell with partners and deliver with juniors. Small ones sometimes pass the work quietly to a freelancer.
Neither is a crime. Not knowing is the problem. Ask who leads, who designs, how many hours a week each person gives you, and whether any of it goes outside the studio. Then meet the lead designer before you sign. If that meeting is hard to arrange now, picture month four. We’ve written more on this in the wrong type of design agency and design studio vs freelancer: the real cost.
Results or shots: what should a case study prove?
That the work changed something. A shot is a beautiful screen on a tilted phone. A case study tells you why the screen exists and what happened after it shipped.
Look for the problem before the solution, the constraints, and a number of some kind: users, installs, funding, retention, an award. If every case study is mood boards and mockups, ask what happened next. A vague answer means the brief was vague, or the work didn’t move anything.
Sector experience counts here too. A studio that has already shipped in your field knows the rules you’d otherwise pay to teach it. We’ve covered what to look for in how to choose a design agency for SaaS and how to choose a HealthTech design agency.
Why do returning clients matter?
They’re the closest thing an agency has to a retention metric. A founder who hires the same studio twice has run this whole checklist with real money and said yes again.
Ask what share of clients come back for a second project. Most agencies don’t know, which is useful information in itself. (Ours is 79%, since you were going to ask.)
What should the contract say?
Who owns the work, how you get out, and what exactly you’re paying for. A good contract is boring. A vague one gets expensive later.
IP transfer.
The final work, source files included, should be yours on payment. Check whether fonts and stock images are included or billed separately.Exit.
There should be a way to stop early, with a clear rule for what you pay and what you receive.Scope and rounds.
Deliverables listed by name, the number of revision rounds, and how extra work is priced.People.
If a named lead is part of why you’re hiring them, put the name in the contract.
None of this is legal advice. Have someone qualified read it, especially if your product is regulated.
The due-diligence checklist
Verified reviews.
Where to look: Clutch or a similar independent platform. Good sign: project detail and a few honest criticisms. Red flag: only homepage testimonials, or perfect scores with no detail.A client call.
Where to look: ask the agency for one or two contacts. Good sign: a recent, similar client, offered without hesitation. Red flag: “Our clients are very busy.”Who does the work.
Where to look: the proposal and a call with the lead designer. Good sign: named seniors, with hours per person. Red flag: “Our team”, no names, or surprise subcontracting.Results, not shots.
Where to look: case studies. Good sign: problem, process, outcome and a number. Red flag: mockups on tilted phones and nothing else.Returning clients.
Where to look: ask them. Good sign: a share they can state, and clients from years ago still around. Red flag: no idea, or only one-off projects.Contract basics.
Where to look: the draft contract. Good sign: IP on payment, a clear exit, scope by name. Red flag: IP kept by the agency, no exit, “unlimited revisions”.
If an agency passes all six, the last question is fit, and you can only answer that one in a room together. If you need help writing the brief you send them, our post on briefing a design studio covers it. If budget is the question, our post on what design costs in Europe has the ranges.
What does a strong result look like? Elli Cares
Here’s the shape we’d want to see, using one of our own. When we started with Elli Cares in November 2023, their app for people living with cognitive impairment had high cognitive load, low contrast and an unclear hierarchy.
We redesigned the website, platform and app around simpler flows, a high-contrast interface and a calm visual language, across reminders, mood tracking, scheduling, location and caregiver messages. The full story is in our Elli Cares case study.
The Elli App is now used in 19 countries and was a joint winner of the 2024 Future of Ageing Award in the Technology Consumer category. The award belongs to their team, and a good case study is honest about where that line sits. What we can point to is a relationship still running since 2023, and this:
“Working with Dtail felt like having a senior team that truly cared about results and users.” Angela Edwards, CEO, Elli Cares
FAQ
How many design agencies should I shortlist?
Three. Fewer and you can’t compare; more and the calls blur into one long, friendly fog.
Are Clutch reviews reliable?
More reliable than homepage testimonials. Clutch says a human editor checks every review, and verified ones carry a badge. Read the detail, not the score.
Is it rude to ask an agency for references?
No. Good studios expect it and have clients happy to take the call. Hesitation is the answer.
Who should own the IP after a design project?
You, once you’ve paid. The contract should say so in plain words and list what’s included, such as source files.
Should I pay for a test project first?
It can work for small, well-defined pieces. For brand or product work, a paid discovery phase usually tells you more than a free pitch.
The two-call test
Pick the studio at the top of your list and ask for two clients you can call: one current, one who finished more than a year ago. Ask both the same thing: would you hire them again, and who did the work? Quick, specific answers mean you’ve found your studio. If the agency can’t set up the calls, you’ve found your answer too.
Vetting us? Fair. Start here and ask for a client to call.
About the author. Slavena Vasileva is Brand Strategist and Partner at Dtail Studio, a senior brand and product design studio in Barcelona working with HealthTech and renewable energy startups. 16+ years, 300+ projects, 5.0 on Clutch.
Sources: G2, 2025 Buyer Behavior Report · Gartner, 61% of B2B buyers prefer a rep-free buying experience · UK Department for Business and Trade, Fake online reviews research · FTC, Final rule banning fake reviews and testimonials · Clutch research methodology · Dtail Studio on Clutch · Elli Cares case study
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