**Overview**: The React Native Android iOS certification validates practical knowledge across building mobile apps with React Native for both platforms. It emphasizes how JavaScript code communicates with native layers through the **bridge** mechanism, and how the same codebase renders UI on Android and iOS. **Exam structure** includes MCQs on project setup, entry points, platform detection via the **Platform** module, native modules, bridging, and debugging. **Domains covered** include project scaffolding, configuration, entry points (index.js, App.js), platform specific code paths, Android and iOS project structure, manifests, deployment basics, and performance considerations. **Why practice matters**: proficiency enables cross platform delivery with native feel while handling permissions, lifecycle, and optimization for a robust user experience. **Recommendations**: build small cross platform features, use official docs, simulate edge cases, review sample projects, and practice under timed conditions to improve problem solving and confidence for interviews or certifications.