How we built Facebook Lite for every Android phone and network

This post details the architecture and engineering decisions behind Facebook Lite, a version of Facebook optimized for emerging markets with low-bandwidth networks and low-spec Android devices. Key technical contributions include a proxy server architecture with a thin client VM, a custom message protocol over TLS to minimize data usage and improve performance on 2G networks, dynamic shared dictionary compression, LZMA2 and DEFLATE compression, image optimization by serving exact-size images from a dedicated server, and a diff mechanism for sending incremental updates. The design also prioritizes minimizing CPU, storage, and RAM usage on the client to ensure compatibility with older devices like Gingerbread-era phones.