Reverse Engineering Linear's Sync Engine: A Deep Dive

This detailed study reverse-engineers Linear's Sync Engine (LSE), showcasing its elegant solution to challenges like supporting arbitrary data models, offering rich features (partial syncing, permission control, undo/redo, offline availability, and edit history), and providing a great developer experience. The author dissects LSE's model definition, MobX usage, bootstrapping process, local database construction, lazy data hydration, client-server synchronization, and undo/redo mechanisms through a deep dive into Linear's frontend code. The article explains how LSE defines models and metadata, performs bootstrapping and lazy loading, and handles transactions, incremental updates, and conflict resolution. LSE aims to empower developers to build collaborative applications without needing to be sync engine experts.