Language packs: Meta’s mobile localization solution

What this post added

This post details the development of a custom mobile localization infrastructure at Meta, featuring downloadable language packs and the FBT (Facebook Translation) framework. It addresses challenges with native Android/iOS localization by supporting gendered text and reducing app size. The post explains the end-to-end flow, construction of language packs, FBT string creation with extraction and structure, and the client-side adoption of language packs, including improvements for poor network conditions like prefetching and fallback mechanisms.