How do I make Apple Watch streaming work from Flutter?

Apple Watch streaming requires a separate watchOS companion target, managed natively in Xcode and written in Swift, even when the main app is Flutter or React…

Apple Watch streaming requires a separate watchOS companion target, managed natively in Xcode and written in Swift, even when the main app is Flutter or React Native (Flutter cannot build watchOS targets). The Flutter/phone side acts as observer.

1

Add the TerraRTiOS framework to the watchOS target.

2

Configure background capabilities in Info.plist.

3

Start realtime streaming with the WATCH_OS connection type, not the phone's apple connection.

The watch then pushes updates to the phone like any BLE device, so no special concurrency handling is needed on the watch side. See connecting a wearable to the SDK on iOS.