Product studio · since 2006
We test the design with the people who’ll actually use it while it’s still a prototype. This way, you can see that it works, and you decide on the full build with real evidence in front of you.
How we made ARDS risk readable at a glance for ICU clinicians
Prototype testedBayer was building ICU Angel, a risk-monitoring platform paired with a drug intervention for ARDS. Clinicians and principal investigators needed to follow a patient's progression and medication response without digging through screens. We designed both views and ran moderated prototype testing across the whole workflow before anything was built.
Prototype tested
Philips needed a new parameter on its bedside monitors. Before any screen was final, we turned the clinical and engineering requirements into 14+ use scenarios, five safety decisions, and uFMEA inputs, so the clinical, risk, and engineering teams could review how the parameter should behave.
InvoiceRate is our own product. Polish sole traders use it to send invoices, pull their purchase invoices from KSeF, and get their records ready for the accountant, all from their phone. We also had to design the screens for when KSeF rejects an invoice, because when that happens, the person needs to know what went wrong and how to fix it.
Live and in use
New users found Euler's risk tiers and collateral rules hard to follow. We ran 12 interviews and collected 200+ survey responses, then simplified the lending and borrowing flows and tested them in two rounds on desktop and mobile.
Usability testedServices
€2,500 from
We review what you have right now and rank every finding by risk, so you know what to fix first. You get a written report and a fix plan to keep.
€9,500 from
This is the Evidence Sprint. We build a working prototype of the riskiest part of your product and test it with real users. You then decide on the full build with the test results in front of you.
€25,000 from
The same team that ran the research designs and builds the product, so the reasons behind each design decision make it into the code.
€2,500 a month
After launch, we stay on as your product team. New features get the same usability checks as the first release, and you get a health report every month.
Industries
In clinical tools and device software, a use error can lead to harm for a patient. That's why we plan the IEC 62366-1 usability engineering file from the first workshop, and don't leave it until the design is finished.
MDR transition ends31 Dec 2027If KSeF rejects an invoice, a lot of finance apps just show the error code from the system behind them. We design the screen that lets the person know what went wrong and what to do next. For us, the failure modes come first, and the happy path comes after that.
KSeF for micro-businesses1 Jan 2027A demo is a simulated environment, but real users paste in messy data and take the answer at face value. We design how your AI feature tells people they're dealing with AI, and how they can recover when the model gets it wrong.
AI Act Article 50since 2 Aug 2026The Fessburn Evidence Loop
Every project goes through the same six stages, whoever on the team is running it. We move to the next stage once the current one has evidence behind it, like a test report or a scope you’ve signed off. This way, what you pay to build is something real users have already tested.
We interview your users and work out which regulations apply to your product.
We build a working version of the riskiest part of the product in a few days.
Real users try real tasks on the prototype, and we write down what happened.
You get a go or no-go and a fixed price for the build. You can stop here.
The same team designs and codes the product and ships it in weekly releases.
When the release is ready, we check it against what we found in testing.
What we commit to
From our clients
“Thank you for creating our website. We loved working with you and appreciate the timely delivery of the pages. It was a great journey thanks to all your hard work.”
“Fessburn has been an excellent company to work with! They are all remote, and so you have to account for some time differences. But they are very responsive to our requests and do excellent work! We have used them for product and web design projects. We highly recommend them!”
“I came across this company through Dribbble. I was pretty hesitant to start, but I was ecstatic with the results. The first version was delivered within 24 hours as promised. I highly recommend them!”
Made by Fessburn
Not all design problems are in the Figma file. Some only show up once you push a product to production and people start using it live. Running our own apps is how we learned to plan for those problems in client work.
KSeF invoicing for Polish sole traders, on iOS and Android
3,000+ usersWrite a post once, approve it, and publish it to 8 social networks
500+ usersFinds leads and runs outreach for sales teams, with voice agents
relaystack.aiTurns a plain-language brief into an AI role you can test before it goes live
In developmentThe team
Every project has a named lead from this team, and you talk to the people doing the work from the first call to the launch.
Questions
Every step has a published starting price. A Diagnose review starts at €2,500, an Evidence Sprint at €9,500, and a full build at €25,000. After our first call, we send you a fixed price for your scope. That price only changes if the scope changes.
Yes. You can start with a Diagnose review or an Evidence Sprint. Each step ends with a document you keep, and you're free to stop after any of them.
Yes. We've done usability engineering on ICU monitoring, diagnostics, and surgical workflows. We plan the IEC 62366-1 usability file from the start of the project, instead of writing it at the end.
You do. Once the invoice is paid, the designs, the code, and the documentation are yours. We'd like to show the project in our portfolio, but if you'd rather we didn't, we'll leave it out.
Yes. The team works from Warsaw and Poznań, in English and Polish, and we work with clients in the EU, the UK, and the US. We plan our calls around your time zone.
We use AI tools to prototype and build faster. A person on our team reviews everything before it reaches you, and we only put your data into tools you've approved.