On May 19, 2021, Coinbase experienced a significant outage that left millions of users unable to trade during a critical market downturn. As cryptocurrency prices plummeted, traders rushed to the platform, creating an unprecedented surge in API requests. Without proper rate limiting and resource controls, Coinbase's systems became overwhelmed, resulting in degraded performance and eventual service unavailability. The incident highlighted a fundamental vulnerability that affects APIs across the industry: unrestricted resource consumption.