Offline First Architecture and Data Synchronization Questions

Designing systems and applications that work seamlessly without network connectivity and reliably synchronize state when connectivity returns. Core areas include local first data models and client side storage strategies, efficient synchronization protocols and delta encoding, approaches for conflict detection and resolution, and trade offs between strong and eventual consistency. Candidates should understand algorithms and patterns such as operational transformation and conflict free replicated data types, optimistic versus pessimistic concurrency, reconciliation and merge strategies, and techniques for preserving ordering and causality such as vector clocks and logical clocks. Practical concerns include batching and incremental sync, retry and backoff strategies, partial and resumable synchronization, idempotent operations, schema migration and versioning, encryption and access control for local data and transport, handling network transitions and intermittent connectivity, background synchronization and push update coordination, and testing and observability for sync correctness and performance. Typical application domains include mobile apps, offline maps, note taking, messaging, and financial or transactional flows where correctness, durability, and user experience during offline periods are critical.