CloudKit is Apple's framework for iCloud data persistence with up to 1PB public storage and automatic cross-device sync.
| CKContainer | Top-level entry point (1 per app typically) | | CKDatabase | Storage layer (private/public/shared) | | CKRecordZone | Logical grouping of records in private DB | | CKRecord | Single data item (like a dictionary) | | CKRecord.ID | Unique identifier (recordName + zoneID) | | CKAsset | Binary data (images, files) |
| CKReference | Relationships between records | | CKSubscription | Push notification triggers |
Apple CloudKit framework for iOS/macOS/watchOS/tvOS development. Use for iCloud data persistence, multi-device sync, CKSyncEngine implementation, CKContainer/CKDatabase/CKRecord operations, conflict resolution, error handling, subscriptions, and CloudKit best practices. Triggers on CloudKit questions, iCloud sync implementation, CKRecord CRUD, zone management, or cross-device data synchronization in Swift/SwiftUI apps. Source: subsc-taha/cloudkit-skill.