#Interview
The road to Sizeless becoming a startup was a long one! “The development was technically demanding, which is why we dreamed, built and validated the university startup ecosystem for several years before it was officially founded,” says founder Leander Peters.
At Sizeless it’s all about size-adjustable children’s shoes. “Our sizeless sneaker is infinitely adjustable in size and covers two sizes in one model. This will be the first favorite sneaker for kids that will still fit after the next growth spurt,” says founder Leander Peters.
In an interview with deutsche-startups.de, the Sizeless maker, who founded the startup 2025 together with Alexander Schemel and Louis Smith in Cologne, talks about the current state of things in his company.
How would you explain sizeless to your grandmother?
Dear grandma, with Sizeless we would have been able to go to the zoo more and go to the shoe store less. Our sizeless sneaker is infinitely adjustable in size thanks to its patent-pending growth mechanism and covers two sizes in one model. This will be the first favorite sneaker for kids that will still fit after the next growth spurt.
How has Sizeless developed since it was founded?
The development was technically demanding, which is why we dreamed, built and validated the university startup ecosystem for several years before the official founding in fall 2025. With the EXIST funding in April 2025, we took big steps towards MVP. After we brought producers on board in the summer of 2025, we were able to test the first samples in the fall. In March we launched a pre-order campaign via Kickstarter to fund production. Over 17,000 euros were raised – more than twice as much as estimated. Almost 200 pairs were pre-ordered directly. We therefore placed the first order in Portugal and will receive a small summer collection in June, limited to 500 pieces. This year will be the year of big steps towards scaling: launching an MVP, testing go-to-market hypotheses and positioning Sizeless as a young kids’ lifestyle brand so that we can grow with 5,000 instead of 500 pairs in 2027.
What was the highlight for you recently?
We have had a Founders Associate on board for a few weeks. This means that the team is expanding to include another “ex-Spoho”, who also has close proximity to the sports industry and adidas through positions at Jung von Matt and the Deloitte Sports Business Group. It’s exciting to see how we are building the core team from the adidas environment – especially since we have just received the first ticket confirmation for our financing from this cosmos.
What has really gone wrong since it was founded?
A few weeks ago we received information that the factory for refining our shoes wanted to increase the cost per pair to 35 euros for this step alone. The shoe would have cost us a total of around 60 euros to produce, which would have destroyed any cost-effectiveness. Luckily we have a sourcing agent on site in Portugal who was able to find a replacement in just two days. Without this local partner, things would definitely have gone wrong so shortly before delivery.
And where have you done everything right so far?
I believe the only correct answer is to have continued despite the mistakes made. We’ve probably made mistakes on every level of business so far. But as long as we perceive them, discuss them and draw our lessons from them, a mistake is nothing more than a practical lesson – something you can never have enough of as a founder.
What three tips would you give other founders?
First: Get out. Talk to your target group and understand what is really needed. If you develop past people, you’ll notice it immediately and save time and money. Second: Build an ecosystem. Find mentors, supporters and other startups. They can’t put out every fire for you, but they can help put it out and advise on what’s highly flammable. Third, be persistent. Don’t be intimidated by conservative industries. When we first visited Portugal, all the factories shook their heads and “experts” told us that a shoe like that couldn’t be built. If we had believed in them and not in ourselves, we would now be at zero instead of 200 pre-orders.
Where will Sizeless be in a year?
Sizeless is not just any children’s shoe. With Sizeless we are redefining how children’s shoes work. And we’ll still be working on that in a year. By then we will probably already have a significantly larger spring/summer collection on sale and at the same time prepare the launch of our winter model. This year the sizeless season runs from summer to fall – next year it won’t end.
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