cloudkit-ref

CloudKit sync enables iCloud data synchronization across iOS, iPadOS, and macOS by storing structured data in private, public, or shared databases. Choose between SwiftData+CloudKit for automatic integration, CKSyncEngine for manual control, or raw CloudKit APIs for custom workflows. Each approach handles conflict resolution differently based on your app's architecture.

SwiftData+CloudKit provides automatic sync with minimal setup; CKSyncEngine offers explicit conflict handling and sync state management; raw CloudKit APIs give full control over database operations and custom logic. Select based on complexity needs: SwiftData for simple apps, CKSyncEngine for structured sync requirements, raw APIs for specialized scenarios.

CloudKit conflict resolution strategies depend on your sync approach. CKSyncEngine and raw CloudKit APIs support server-wins, client-wins, and custom merge logic. Implement handlers that detect version mismatches, apply business rules to conflicting records, and persist the resolved state to maintain consistency across private, public, and shared databases.

Yes. CloudKit supports three database types: private (per-user iCloud), public (app-wide), and shared (user-initiated collaboration). Configure appropriate entitlements and access controls for each database type. CKSyncEngine and raw APIs handle multi-database sync workflows, managing permissions and conflict resolution independently per database.

Monitor sync state, track record change timestamps, and analyze network activity to identify bottlenecks. CKSyncEngine exposes sync progress and error details; raw CloudKit APIs provide operation callbacks. Check for excessive record sizes, unindexed queries, rate limits, and misconfigured entitlements that degrade sync speed across devices.

Enable iCloud capability, configure CloudKit container entitlements, and set up database schemas and indexes in CloudKit Dashboard. SwiftData+CloudKit automates schema mapping; CKSyncEngine and raw APIs require manual record type and field definitions. Verify sandbox and production environment settings match your app's deployment target.