SwiftData
Apple's modern Swift-native persistence framework, introduced in iOS 17 as the declared replacement for CoreData. SwiftData uses Swift macros (@Model, @Relationship, @Attribute) to define persistent model classes — no manual entity descriptions, no NSManagedObjectContext boilerplate. Integrates tightly with SwiftUI via @Query macro for reactive data fetching. Backed by CoreData under the hood but with a dramatically simpler Swift-native API.
Score Breakdown
⚙ Agent Friendliness
🔒 Security
Data stored in app sandbox — isolated from other apps. iOS Data Protection class for encryption at rest. No network exposure. CloudKit sync is E2E encrypted when configured.
⚡ Reliability
Best When
You're building a new iOS 17+ app that needs local persistence and want a Swift-native ORM without CoreData's Objective-C heritage and boilerplate.
Avoid When
You need to support iOS 16 or earlier, need complex CoreData predicates, or are building server-side Swift — use CoreData or Realm Swift for broader compatibility.
Use Cases
- • Persist agent-generated content and user data in iOS apps using @Model classes without CoreData's manual entity setup and NSManagedObjectContext
- • Build reactive SwiftUI agent interfaces using @Query to automatically update views when persisted data changes — replaces NSFetchedResultsController
- • Store offline agent data with automatic schema migrations — SwiftData handles lightweight migrations automatically when @Model properties change
- • Create relational data models for iOS agent apps using @Relationship for one-to-one, one-to-many, and many-to-many associations
- • Implement undo/redo for agent data operations using SwiftData's ModelContext undo manager integration with SwiftUI environment
Not For
- • iOS 16 or earlier — SwiftData requires iOS 17+; use CoreData for backwards compatibility
- • Complex query requirements — SwiftData's predicate system is less powerful than CoreData's NSPredicate for complex queries; CoreData may be needed for advanced cases
- • Server-side Swift persistence — SwiftData is iOS/macOS framework; use Vapor + Fluent or Hummingbird for server-side Swift persistence
Interface
Authentication
SwiftData is a local persistence framework — no auth. Database files are protected by iOS app sandbox and optionally encrypted with Data Protection class.
Pricing
SwiftData is part of Apple's frameworks, bundled with Xcode and iOS SDK. Free for all Apple developer program members.
Agent Metadata
Known Gotchas
- ⚠ SwiftData requires iOS 17+ — if your app supports iOS 15/16, you must maintain parallel CoreData/SwiftData code paths or use Realm Swift for broader compatibility
- ⚠ Schema migration is limited to lightweight migrations — adding/removing properties works automatically, but non-trivial migrations (type changes, computed migrations) require manual migration stages
- ⚠ @Query in SwiftUI runs on main thread — heavy queries in @Query can block UI; move complex aggregation to background ModelContext with modelContext.perform { } pattern
- ⚠ ModelContext is not thread-safe — never access the same ModelContext from multiple threads; use separate ModelContext instances per actor/thread for concurrent agent data operations
- ⚠ Relationships with @Relationship(deleteRule: .cascade) — forgetting delete rules causes orphaned objects; orphans accumulate silently and may cause predicate query performance issues
- ⚠ CloudKit sync via SwiftData requires ModelConfiguration(cloudKitDatabase: .automatic) — not just .init(); sync conflicts are handled automatically but agent writes during sync may be delayed
Alternatives
Full Evaluation Report
Detailed scoring breakdown, competitive positioning, security analysis, and improvement recommendations for SwiftData.
Scores are editorial opinions as of 2026-03-06.