Zalando shifts load balancing to the client side

Zalando — the German e-commerce giant with $16B in annual revenue — is moving its load balancing logic from the server side to the client side. The idea is simple: instead of each server figuring out which backend should handle a request, the client decides before making the call. This cuts out a hop, reduces latency, and scales more cleanly as traffic grows.

Client-side load balancing has been around for years in distributed systems, but Zalando's move highlights why it's gaining traction now. As traffic patterns get more unpredictable — peak seasons, flash sales, holiday rushes — having clients route their own requests means the system stays responsive without needing to overprovision servers. The tradeoff is that clients get smarter and more complex, but the payoff is speed and cost savings at scale.

Why this matters for us: the apps and services we use every day — from delivery tracking to payment processing — are all built on systems like this. When companies figure out ways to make them faster and cheaper, that usually means faster service and lower costs for people who depend on them.