RN app does not hot reload

Context#

• Environment:
  • React Native 0.76.8
  • Xcode 16.4
• What I was doing:
  • Built and run RN app on Xcode, but running Metro on terminal

The Error#

RN app does not hot load, pressing r in Metro session will display no apps connected error, no matter running on emulator or physical device.

...
debug Key pressed: r
info Reloading connected app(s)...
warn No apps connected. Sending "reload" to all React Native apps failed. Make sure your app is running in the simulator or on a phone connected via USB.

Updates in code not reflected in the running app until rebuild and rerun the app.

Root Cause#

The app is not in debug mode. For example, the “Build Configuration” in XCode was set to Release

The Fix#

1. Go into Xcode, open your project
2. Press [⌘]+[⇧]+[,], or go from menu Product -> Scheme -> Edit Scheme
3. Make sure in the new window that Run is selected
4. Ensure the Build Configuration is set to Debug (could be set to Release and that’s why it’s not working)
5. Click Close
6. Press [⌘]+[⇧]+[k] to do a full clean of the build folder
7. Try running it on device again.

References#

• React Native does not hot-reload on ios device : r/reactnative ↗