native-data-fetching

Use the fetch API with explicit error handling: check response.ok before parsing JSON and throw typed errors for HTTP failures. For Expo apps, prefer expo/fetch over axios, and wrap requests in a reusable API client configured with your base URL.

React Query (TanStack Query) suits complex apps needing mutations, cache invalidation, and offline persistence, while SWR fits simpler fetching needs. React Query also handles request deduplication and automatic cancellation on unmount.

Store tokens in expo-secure-store, never in AsyncStorage, which is not encrypted. Implement a token refresh flow that deduplicates concurrent refresh attempts and attaches the valid token to requests via an authenticated fetch wrapper.

Use EXPO_PUBLIC_ prefixed variables in .env.development and .env.production files, accessed via process.env in code. Only EXPO_PUBLIC_ variables reach the client bundle, so keep secrets in non-prefixed variables used only in API routes.

Detect connectivity with @react-native-community/netinfo and sync it to React Query via onlineManager so queries pause offline and resume online. Combine this with React Query persistence to cache data across sessions.

Fetch does not throw on HTTP error statuses, so calling response.json() without checking response.ok hides failures. Always validate the status code, parse error bodies, and distinguish network errors from HTTP errors with typed error classes.