Apple's Password Monitoring Service Gets a 40% Performance Boost with Swift Rewrite

Apple migrated its global Password Monitoring service from Java to Swift, resulting in a 40% throughput increase and a significant reduction in memory usage—freeing up nearly 50% of Kubernetes capacity. The switch addressed performance bottlenecks stemming from Java's garbage collection and high memory footprint. Swift's deterministic memory management and faster startup times drastically improved scalability and responsiveness. Handling billions of daily requests with stringent latency requirements, the service benefited greatly from Swift's performance. This migration reflects a broader industry trend toward performance-oriented languages for extreme-scale services.