Unified stock for 74 stores and the online platform

The challenge

Stock was synchronised once a night. During campaigns that meant accepting orders for products already sold out: 6.8% of Black Friday orders were later cancelled, with a direct effect on reputation.

In parallel, the online platform buckled at eight times average traffic, and the team had no visibility into the causes.

The solution

We introduced a central inventory service, fed by events from the point-of-sale systems and the warehouse system.

• Stock changes propagated across all channels in under ten seconds
• Temporary stock reservation at the moment an item is added to the basket
• Catalogue search moved to a dedicated engine, with a 40 ms median response
• Autoscaling driven by request queue depth, not just CPU usage

We ran three campaign simulations before Black Friday, at twelve times average traffic.

The outcome

Cancellations caused by unavailable stock dropped from 6.8% to 0.4%. The platform carried Black Friday 2025 without degradation, at a peak of 14,000 concurrent users.

Infrastructure cost rose by only 18% year on year, although traffic grew by 63%.