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System Design1 min read

Offline-First Android System Design

Designing sync, conflict resolution, local projections, and UI states for Android apps that must work through weak networks.

System DesignRoomDBFirebaseClean Architecture

User Trust Comes First

Offline-first architecture is not only about caching. It is about giving users predictable behavior when connectivity changes.

Core Pieces

UI -> ViewModel -> UseCase -> Repository
Repository -> LocalDataSource + RemoteDataSource + SyncManager

Local Projections

Store local projections that are shaped for screen reads. This keeps the UI fast and reduces repeated mapping work.

Conflict Resolution

Use server timestamps for simple feeds, domain-specific merge rules for collaborative workflows, and explicit user decisions for destructive conflicts.

Observability

Track sync latency, queue depth, retry counts, and failed mutations. Production sync needs dashboards, not just optimistic code.

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