Improving Facebook on Android

This post details significant improvements made to the Facebook Android app focusing on performance, data efficiency, networking, and application size. Key contributions include: deferring non-critical initializations to improve startup times, fetching News Feed stories earlier for faster loading on poor networks, optimizing image downloads using WebP compression (25-35% savings over JPG) and adaptive resolution loading based on viewport size, and fine-tuning image caching strategies. The networking stack was enhanced by adopting OkHttp, enabling faster retries and SPDY protocol support, leading to a 90% reduction in slow/failed image loads. Application size was reduced by 65% by utilizing Google Play's ability to upload multiple APKs for different device configurations. Automated tests and instrumentation were developed to monitor and prevent regressions in data usage and app size.