• YEAR 2012 halves out of stocks has been the undisputed number 1 online retailer for books and entertainment in the Netherlands for years. However, the e-tailer is now well on the way to attaining this status in a number of other product categories. To help manage the business’ rapidly growing assortment, depend on Slimstock’s inventory management solution, Slim4. With support from the inventory management experts at Slimstock, the online retailer can now ensure that the enormous assortment of more than 8 million active SKUs is managed effectively. 

Since its launch as an online bookseller, the e-tailer has expanded significantly and now offers products across a broad range of categories including cosmetics, jewellery, home furnishings and toys, amongst others. “Our range currently consists of dozens of sub-categories” explains Caspar Kerkvliet, Director Supply Chain & Contracting. The complete range encompasses over 8 million active SKUs, of which thousands are stocked at the e-commerce fulfilment centre located in the South of the Netherlands. 



  • 50% reduction on stockouts
  • 1% increase in order fulfilment
  • Increase in both profitability & customer loyalty

Millions of SKU's recalculated in just 1 hour

The supply chain & contracting director explains: "We are becoming increasingly active in product categories that require far more intensive stock control. Furthermore, for new markets, the uncertainty in the supply chain is often much greater than sectors where are well established.” As a result, took the strategic decision to implement Slimstock’s inventory optimisation tool, Slim4.


“We needed an exceptionally powerful standard solution that could offer scalability,” states Kerkvliet. As part of a stress test, Slim4 was able to re-calculate millions of SKUs within just one hour. “For us, this was convincing evidence that the solution had the capability to deal with the size of our assortment.”

Management by exception

Thanks to Slim4, the team at now receive notifications for all exceptions.  As a result, online retailers can work more efficiently. Kerkvliet goes on to add: "In addition, with the help of Slim4, we can manage capacity planning much more tightly during the peak months of November and December. This, in turn, enables us to ensure a timely build-up of inventory.” 

The service levels have also been improved considerably: “Since we started working with Slim4, the number of stockouts has been halved. Furthermore, our availability has increased by several percent despite substantial growth in revenue.”

Better service leads to greater customer loyalty

With Slim4, the team at are better positioned to determine whether products should be kept in stock or whether they should be stocked by the supplier. The software helps the business to balance inventory and order costs with the additional turnover that could be generated by if the product was stocked and therefore available for same day delivery. “We have already benefited from this. Ultimately, we are better able to deliver products as and when our customers demand them,” states Kerkvliet proudly. “Our fulfilment rates have increased by over 1% and we are now able to maintain a good service level across all products. In the short term, this has resulted in a turnover increase. However, in the long term this will help to encourage customer loyalty: And in our industry, that is the ultimate goal!”

"With the help of Slim4, availability increased and we realised substantial revenue growth."