How Catawiki Runs Worry-Free Experimentation at Scale with ABsmartly

When your business relies on real-time decisions, dynamic pricing, and interactions between buyers and sellers across more than 60 countries, even small missteps can snowball quickly. Catawiki, Europe’s leading online auction marketplace for collectibles, has professional curators reviewing every listing and most transactions crossing borders, so their business is built on both expertise and complexity.

From early on, Catawiki recognized that experimentation would be key to navigating that complexity. But as the company grew, its A/B testing system began to buckle under the pressure. Engineers were stuck fixing bugs instead of shipping tests. Teams lost confidence in results, and the experimentation system that was once a competitive advantage started slowing them down. To keep moving fast and trust in every decision, Catawiki needed an infrastructure they could rely on and a partner who would support them.

Catawiki’s Experimentation Pain Point

Catawiki didn’t wait to take experimentation seriously. From the start, they built with intent, creating an in-house experimentation tool. That foundation gave them a head start, and for a while, it worked. Teams moved quickly, and experimentation became part of the company’s DNA.

But speed has a price if your infrastructure can’t keep up. As Catawiki scaled to 10 million monthly visitors and ran over 120,000 auctions at any given time, cracks in the system started to show. Engineers were constantly pulled away from product work to patch bugs in the testing platform. Reports took longer to generate. Trust in the results began to fade. For a business that thrives on precision and real-time decisions, that loss of confidence was a red flag. According to Henk Smit, Senior Director of Data, “People had lost trust in the old framework. Now everyone rallies around ABsmartly, but before that, we knew something had to change.”

Catawiki Didn’t Just Need a Platform, They Needed a Partner

When Catawiki started exploring external experimentation platforms, they were looking for something their in-house system could no longer provide: trust, consistency, and support at scale. Most tools promised ease of use, drag-and-drop interfaces designed for non-technicalteams. But Catawiki is a technical organization. Their engineers, data scientists, and product managers didn’t want a simplified sandbox. They wanted precision, control, and flexibility that could meet them where they already were.

When Henk suggested they take a closer look at what ABsmartly could offer, it was a forgone conclusion. Migration would be seamless, and unlike larger vendors, where Catawiki often felt like just a number in a queue, ABsmartly showed up as a true partner from day one. “That is the best part for us,” Henk shared. “With ABsmartly, we feel listened to. The collaboration has been exactly what we needed.”

The transition was smoother than expected. With their existing pipelines already in place, Catawiki was able to connect its internal data flows directly into ABsmartly. Within weeks, they were up and running with experiments that were more transparent, consistent, and trustworthy than ever. “We had a head start because of our existing framework,” Henk said. “But ABsmartly gave us the reliability we were missing.”

More Experiments. Fewer Distractions. Better Decisions

Working with ABsmartly changed how teams at Catawiki work. Before, experiment results were often met with hesitation. The data seemed questionable, and decisions dragged on. Now, teams across Catawiki rely on a single, trusted source of truth. Product managers, engineers, and analysts all review results in ABsmartly, confident that what they’re seeing is both statistically sound and immediately actionable.

That renewed trust has had ripple effects. Catawiki now runs Catawiki has new experiments starting every day across 10 product teams, testing everything from registration flows to bid steps. With real-time monitoring in place, issues are caught early, and teams can make adjustments quickly if something isn’t working. What used to take weeks of debate now gets resolved in days or sometimes hours. And the gains aren’t just on the surface. Engineers no longer have to babysit a fragile system. Data teams have shifted from maintaining infrastructure to focusing on meaningful analysis and insights. 

“ABsmartly has helped us save up to 50% of the time spent setting up, tracking, and concluding experiments — and 100% of the time spent on tool maintenance — compared to our previously in-house-built experimentation platform,” says Henk. “Our team can focus on improving the product and customer experience instead of babysitting experiments.”

For a marketplace that thrives on trust and engagement, that shift is critical. It means the team can spend less time fighting fires and more time building features that make the experience better for both buyers and sellers.

How Catawiki Embedded Experimentation

For plenty of companies, working with ABsmartly is the start of their experimentation journey. For Catawiki, it was something else entirely: a way to reinforce what was already working and protect it as they scaled. Experimentation had long been part of Catawiki’s culture. Teams were trained in it. Processes were in place. New hires learned the importance of testing early. However, as the business grew, what they needed wasn’t more rules or a rigid structure; it was a system that could keep pace with their maturity without creating friction.

ABsmartly gave them exactly that. Our platform’s reliability made it easier to standardize practices, without boxing teams in. Because the data was trusted and the tooling stable, teams could spend their energy where it mattered most: crafting hypotheses, defining metrics, and then learning from outcomes. No more second-guessing the framework. No more worrying if the numbers would hold.

As Henk puts it, “We still allow space for intuition when needed, but we always want to know with confidence whether something really works. ABsmartly helps us strike that balance.”

That balance between flexibility and rigor is what keeps experimentation healthy at Catawiki. Teams hold regular reviews, share learnings, and measure experimentation maturity over time. The mindset isn’t enforced; it’s lived. And ABsmartly plays a quiet but crucial role in keeping it that way.

Worry-Free Experimentation as a Growth Driver

Catawiki treats experimentation as a critical business function that needs to be supported like any other core system. They have a complex business with over 120,000 auctions live at any moment, a user base spread across 60+ countries, and a two-sided marketplace where buyers and sellers need different things yet still rely on a shared platform experience. In that kind of environment, gut instinct isn’t enough. A reliable experimentation platform and a team that’s there to support you when it matters is the only way to break things fast and make them even better. 

Our partnership with Catawiki shows what is possible when a company with strong experimentation DNA pairs its culture with the right technology. Their business is complex, their marketplace is dynamic, and their customers expect trust at every step. By moving from a fragile homegrown framework to ABsmartly, they have turned experimentation from a potential bottleneck back into a growth driver.

With more experiments running each quarter, a culture that balances rigor with flexibility, and a partner who listens and adapts alongside them, Catawiki can continue to scale without compromise. For Henk and his team, this means no longer worrying about whether the infrastructure will hold up. Instead, they can focus on what really matters: solving problems for buyers and sellers, refining the customer experience, and building a marketplace that continues to grow in both reach and impact.

As Henk Smit puts it, “At Catawiki, making the right decisions about which new features to roll out and which to take back to the drawing board is the difference between growth and stagnation — it’s the lifeline of our business. AB Smartly empowers us to do just that.”

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