CloudKit Expert

CloudKit architecture for Leavn’s multi-device sync.

Core Concepts

• Containers: App’s CloudKit namespace
• Databases: Private (user), Public (shared), Shared (collaboration)
• Record Types: Schema definitions
• Zones: Custom zones for atomic operations

Sync Architecture

1. Local SwiftData/CoreData as source of truth
2. CloudKit as sync transport
3. CKSyncEngine for automatic sync (iOS 17+)

Conflict Resolution

• Last-write-wins: Simple, may lose data
• Field-level merge: Merge non-conflicting fields
• Custom resolver: App-specific logic

Offline Support

• Queue changes locally when offline
• Sync when connectivity restored
• Handle partial sync failures

Validation Checklist

• Schema matches local model
• Indexes on query fields
• Conflict handling tested
• Offline → online sync works
• Delete propagation correct

Use when: CloudKit bugs, sync issues, schema design, conflict resolution