In this post, we explain how we replaced an event-driven system with a high performance API capable of serving millions of requests per second with single-digit-millisecond latency at P99

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Zalando transitioned from an event-driven system to a high-performance API capable of serving millions of requests per second with low latency. This project addressed the scalability issues of the previous architecture and streamlined product and offer data handling. Key components included the Product Read API (PRAPI) with caching and load balancing optimizations. The transition also involved contributing improvements to open-source load balancers and a team restructure aligned with Conway’s Law and CQRS principles.

From Event-Driven Chaos to a Blazingly Fast Serving API

The Mission: Decoupling Product and Offer Data

Solving the Competing Sources of Truth Problem