Spotify Modernizes Client-Side Architecture to Accelerate Service on All Devices

This post details a significant modernization of the client-side architecture to improve the listening experience on all devices, particularly addressing performance issues on older phones and slower networks by optimizing how Liked Songs metadata is loaded and stored locally. This involved a substantial refactoring of the client codebase, replacing in-memory sorting with pre-computed tables stored on disk, and implementing batched downloads. The project required modifying approximately 100,000 lines of code in the shared client codebase and tweaking both Android and iOS apps to ensure feature parity and support for new UI trends.