What a strong React Native developer actually knows
React Native is JavaScript on the surface and platform engineering underneath. A developer worth hiring writes clean TypeScript, but also understands the new architecture with Fabric and TurboModules, how the Hermes engine affects startup time, and why a long list needs FlatList or FlashList rather than a plain ScrollView. They treat the bridge, the main thread and the JS thread as separate things to protect.
Navigation, state and data fetching are where most apps succeed or sag. Expect experience with React Navigation or Expo Router, a deliberate choice between Redux Toolkit, Zustand and React Query, and offline behavior that has been designed rather than hoped for. Good candidates can explain why they picked each tool and what it cost them. Those reasons are what you are really paying for.