"A test is worth more than 1,000 expert assumptions," stated the founder of Velux, Villum Kann Rasmussen. We agree. With a webshop that should be able to handle any size and type of their complex product selection, the only option was to prototype the interactive experience. That way, we could test, test, and test the experience before investing hours and budget into the development. We designed a fully-functional webshop prototype with the Velux team in five weeks. It illustrated the core user flows in a responsive prototype, allowing us to work with real data and test and learn fast. Velux tested the final solution in three markets before continuing the development in-house