400 React Native Interview Questions with Answers 2026

Navigation & State: React Navigation, Redux Toolkit, Zustand, Context API, and Auth Flows.

Performance & Native: Fabric, TurboModules, Memoization, FlatList optimization, and Profiling.

API & Security: REST/GraphQL, Axios, MMKV, JWT Authentication, and Secure Storage.

Testing & Deployment: Jest, Detox, Flipper, CI/CD, and App Store Submission.

B) It acts as a JSON-based asynchronous messenger between the JS thread and Native modules.

C) It replaces the need for the Yoga layout engine in modern versions.

D) It directly compiles JavaScript into Objective-C or Java code at runtime.

E) It manages the lifecycle of TurboModules via JSI.

F) It is responsible for rendering shadows on Android devices without external libraries.

Correct Answer: B

Overall Explanation: In the legacy architecture, the Bridge is the communication layer that allows the JavaScript thread and the Native thread to talk to each other via asynchronous JSON messages.

Option Explanations:

B is correct: This describes the primary function of the Bridge (asynchronous JSON serialization).

C is incorrect: Yoga is the layout engine; the Bridge is for communication.

D is incorrect: React Native does not compile JS into native code; it executes JS in a VM.

E is incorrect: TurboModules use JSI (JavaScript Interface), which bypasses the Bridge.

F is incorrect: The Bridge has nothing to do with specific UI rendering like shadows.

Question 2: When optimizing a large list in React Native, why might you choose getItemLayout in a FlatList?

B) To automatically cache images used within the list items.

C) To skip the measurement of dynamic content and improve performance by providing predefined offsets.

D) To force the list to render all items at once (disabling virtualization).

E) To integrate the list with the Reanimated library for 60FPS animations.

F) To handle deep linking within individual list rows.

Correct Answer: C

Overall Explanation: getItemLayout is a significant performance optimization that tells the FlatList the height/offset of items beforehand, skipping expensive layout calculations.

Option Explanations:

B is incorrect: Image caching is handled by the Image component or libraries like react-native-fast-image.

C is correct: By providing the offset, the list knows exactly where an item is without measuring it.

D is incorrect: This would destroy performance, whereas getItemLayout improves it.

E is incorrect: While related to smooth scrolling, it is not a Reanimated-specific feature.

F is incorrect: Deep linking is a navigation concern, not a layout concern.

Question 3: In the context of React Native security, what is the primary disadvantage of using AsyncStorage for sensitive data like Auth Tokens?

B) It encrypts data using a weak 64-bit key by default.

C) It stores data in plaintext, making it accessible on rooted or jailbroken devices.

D) It can only store strings, which makes it impossible to store JWTs.

E) It causes the app to crash if the device runs out of RAM.

F) It is deprecated and no longer works on iOS 17+.

Correct Answer: C

Overall Explanation: AsyncStorage is an unencrypted, key-value storage system. For sensitive data, developers should use Keychain (iOS) or Keystore (Android) via libraries like react-native-keychain.

Option Explanations:

B is incorrect: AsyncStorage provides no encryption by default.

C is correct: Data is stored in cleartext; anyone with file system access can read it.

D is incorrect: JWTs are strings, so they can be stored; it's just not secure.

E is incorrect: It is persistent storage (disk), not strictly RAM-bound, and rarely causes crashes.

F is incorrect: It is still widely used for non-sensitive data and remains functional.

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