UnitedHealth Group's Optum successfully transitioned from a closed-source API gateway to the open-source Kong Gateway to address issues of scalability, performance, and cost-effectiveness. The move aligned with a broader organizational shift towards embracing open-source solutions, which offered greater extensibility and eliminated licensing fees. Optum implemented Kong with a focus on improving DevOps capabilities, integrating security measures, and establishing efficient API gateway patterns. They developed a self-service model using GitHub for efficient customer interactions, significantly reducing manual operations and enhancing developer productivity. The transition resulted in an 85% reduction in gateway overhead and a 90% increase in resource efficiency, drastically lowering operational costs by 95%. The adoption of Kong led to a substantial increase in performance and scalability, with the platform managing over 11,000 proxies and 4.5 billion transactions monthly by 2020, marking a ten-fold growth from 2019.