Offline-First PWA / Mobile Sync - Service workers, IndexedDB, background sync, CRDTs for annotations. Read on plane, sync later. #1007406

A practical guide to building progressive web apps that work offline. Covers service workers, the Cache API, IndexedDB, background sync, outbox queues, conflict resolution, and CRDT-based annotation merge. Built around a real annotation reader that reads on a plane and syncs later — with the failure modes that destroy user work, and the code that prevents them.