In the fast-paced world of financial trading, speed, and efficiency are essential. To achieve this, vertical scalability is crucial in order-processing systems. However, achieving vertical scalability can be a significant challenge for developers. That's why testing is critical.

Vertical scalability is achieved by minimizing accidental complexity and using an event-driven architecture. With consistent latencies of 1 to 10 microseconds and throughputs of 100k to 1,000k msg/second, the focus should be on testing that prioritizes business requirements. This approach ensures higher performance by doing as little as possible. Since vertical scalability is critical in financial trading systems, we will explore testing techniques and best practices that prioritize business requirements and minimize accidental complexity to achieve higher performance.