Swift Observation

Observation

What to open

• Use swift-observation/observation.md for full API details and examples.
• Search within it for @Observable, withObservationTracking, ObservationRegistrar, Observations, and ObservationIgnored.
• Use swift-observation/observations_pre_iOS_26_backport.md for availability notes and backport discussion.
• Use swift-observation/Observation/ source files to inspect the Observations implementation and any supporting runtime pieces when evaluating backport feasibility.

Workflow

• Prefer @Observable to make models observable; do not conform to Observable manually.
• Read properties inside withObservationTracking to define the dependency set.
• Use ObservationIgnored for properties that should not trigger updates.
• Use Observations when you need async change streams.

SwiftUI usage

• For SwiftUI, treat @Observable models as the source of truth and let the view read the properties it needs.
• Use withObservationTracking for non-SwiftUI rendering or custom observers.

Availability and backport notes

• Observations is available on iOS 26+; plan for fallbacks on earlier OSes.
• For pre-iOS 26 support, consider community backports or vendor forks; see swift-observation/observations_pre_iOS_26_backport.md for options and caveats.