How do you test a business idea without investing months or even years into development? That exact question was what we asked ourselves, and we turned it into an experiment: Can we develop a working app within just seven days that real users can test?
Why many business ideas fail before they even start
Every year in Germany hundreds of thousands of new companies are founded. At the same time many founders give up their businesses. According to the Statistischen Bundesamt in 2025 around 640,500 businesses were newly registered, while at the same time about 502,200 businesses were completely closed.
Behind every business idea are time, money and resources. Especially for digital products the same mistake often occurs: companies invest months in planning and development before they even find out if their product is needed in the market.
The problem is: if only after six or twelve months it becomes clear that customers don't want the product, high five- or even six-figure amounts can quickly be lost.
Our experience: Why we wanted to do it differently this time
We know this problem from personal experience too.
With our app Humafix we experienced how a first idea turned into a finished product over many years. From the original vision to a market-ready solution it took about seven years.
That's why we wanted to do it differently this time.
Instead of discussing features, designs and future possibilities for a long time, we wanted to find out as quickly as possible:
Is there genuine interest?
Do users understand the value?
Are people willing to pay for it?
Can a sustainable business model be developed from it?
For that, we set ourselves a clear deadline of seven days.
The challenge: Develop an app in just one week
The goal wasn't to build the cheapest app. The goal was to create a product within one week that real users can test. Speed was prioritized over perfection.
Because a working MVP (Minimum Viable Product) answers the most important questions much faster than months of planning:
Do people use the product?
Do they understand the use case?
Does the solution work in everyday life?
Is the problem big enough that users will take action?
The example: How broobie was created
For our experiment we developed the broobie app.
The starting situation:
Many women wear the wrong bra size or are unsure which bra style actually suits their body shape and needs.
This is exactly where broobie comes in.
The app helps women to:
take their measurements correctly,
find suitable bra styles,
receive personalized recommendations,
save their measurements,
track changes over time.
Additionally, we have already integrated features that enable later monetization:
Stripe payments for a Pro version
Booking personal consultations
Multilingual support (German and English)
Our MVP process: How we used the seven days
A key success factor was working in parallel.
While Lena developed the concept, the user journey and the content, Ben focused on the technical implementation.
This allowed us to advance several areas at the same time:
Concept and landing page
At the beginning, a landing page was created that allows interested visitors to sign up.
User acquisition was considered from the very first step.
Registration and onboarding
We then developed the registration process including:
Email login
Google login
Apple login
This is followed by onboarding, in which the user specifies her needs and requirements.
Quiz and product recommendations
Based on various questions about:
Fit
Comfort
Previous experiences
Individual preferences
the app provides recommendations for suitable bra shapes.
Measurement process
The user receives step-by-step instructions for taking measurements correctly.
The captured data can then be stored permanently and compared.
Payment features and finishing touches
Finally, we integrated:
Stripe payments
Consultation bookings
User profiles
Favorites feature
The app went live after just one week.
The most important insight: the last 20% often takes the longest
An important lesson from the project:
The first 80% of a product often come together much faster than expected.
The last 20%, on the other hand, can quickly turn a few days into several weeks.
Suddenly it's about:
Small design tweaks
Text corrections
Optimizations for specific devices
Edge cases in user behavior
This is exactly where many teams lose valuable time. They push the launch back by a day. Then by another week. And before long, an MVP project turns into a long-term development project.
That's why we kept asking ourselves the same question:
Does the user really need this feature to test the product?
If the answer was "No", the feature was postponed.
What an MVP really needs to deliver
Many founders confuse an MVP with an unfinished version of a product.
That's a misunderstanding. A good MVP doesn't have to include all features.
A good MVP only needs to provide enough value to answer the following questions:
Do people have a real problem?
Do they understand the solution?
Are they actively using the product?
Are they willing to pay for it?
Only when these questions are answered positively is further investment worthwhile.
Why real user contact is more important than perfect planning
The real learning process only begins after launch.
Only when real users use the product do valuable insights arise:
Where do users drop off?
Which features are being used?
Which areas do users ignore?
Which assumptions were wrong?
No market analysis and no workshop can replace these insights.
That's why the product launch was the most important milestone of the entire project for us.
Can an MVP already make money?
Yes. An MVP doesn't have to be free.
On the contrary:
If customers are willing to pay for an early product version, that's often one of the strongest indicators of true product-market fit.
On broobie, users can already book the Pro version and buy personal consultations.
These revenues can flow directly into further development of the product.
Our conclusion: Test first, then perfect
After seven days we still don't know whether broobie will become a big and successful product.
But that was never the goal. The real goal was to bring the idea out of our heads and into reality.
Today we can:
Collect real user feedback
Analyze data
Validate hypotheses
Make informed decisions
And that's exactly the biggest advantage of an MVP.
It's not perfection that determines the success of an idea, but the speed at which you gain real insights.
Have an app idea? Test it instead of planning for months
Together we will develop an MVP that real users can test and that quickly gives you the data you need for your next decisions.
#Test a business idea#Custom web app development#develop an app#Product development#Tailored software solutions