Reliability is a fundamental aspect of the Nylas API platform, which prioritizes a high standard of API success rates over mere uptime metrics to ensure predictable performance for developers. Nylas emphasizes the importance of designing their infrastructure with reliability as a core engineering principle, using dedicated infrastructure over Kubernetes for certain components to enhance performance and latency control. They implement data-driven canary deployments, using real-time monitoring to halt and roll back releases if even minimal regression is detected, ensuring every change enhances the developer experience. Additionally, continuous chaos testing is conducted to simulate real-world failures, allowing for early identification of hidden dependencies, hardening of retry logic, and verification of platform stability. This approach has enabled Nylas to achieve a significant improvement from 99.9% to 99.99% API reliability, reducing downtime and enhancing customer trust, ultimately fostering a culture that views reliability as an ongoing commitment rather than a one-time goal.