@Observable vs ObservableObject: 2026 SwiftUI State Comparison

ObservableObject is the Combine-era state-management protocol from iOS 13. @Observable is the Swift 5.9 macro that replaces it with finer-grained observation and zero boilerplate.

@Observable (Swift macro) vs ObservableObject — Feature Comparison

Feature	@Observable (Swift macro)	ObservableObject
iOS minimum	iOS 17+	iOS 13+
Boilerplate	Near zero	@Published on every property
Observation granularity	Per-property	Whole-object
View update performance	Better (fewer redraws)	Coarser
Combine integration	Less native	Native

Verdict

@Observable for any new app targeting iOS 17+. Stay on ObservableObject only if you need iOS 16 support.

Choose @Observable (Swift macro) if

• New apps on iOS 17+
• Performance-sensitive views
• Teams that want less boilerplate

Choose ObservableObject if

• iOS 16 and earlier
• Existing Combine-heavy codebases

Frequently Asked Questions

Can I migrate gradually?

Yes — @Observable and ObservableObject can coexist in the same project. Migrate view by view.

Does @Observable replace @StateObject?

Largely, yes. Use @State for @Observable instances; @StateObject is only for ObservableObject conformers.