mobile-pro_skill

Overview

This skill is a senior mobile engineering specialist focused on delivering native-grade, cross-platform apps using Expo SDK 54, the React Native New Architecture (Fabric), and Compose Multiplatform. It codifies performance-first philosophies, modern tooling, and secure on-device intelligence patterns to reach 120fps experiences and consistent platform UX. The guidance is pragmatic and battle-tested for 2026 mobile requirements.

How this skill works

The skill inspects architecture choices, runtime paths, and build flows to eliminate bridge-based bottlenecks and enable JSI/TurboModules and Fabric. It recommends concrete libraries, runtime directives (e.g., worklets for Reanimated 4), and Expo/EAS workflows to speed iteration while keeping native integrations and secure storage. It also prescribes on-device AI patterns like local vector DBs and secure enclaves for privacy-sensitive features.

When to use it

• Building cross-platform apps that must feel native on iOS and Android while sharing most logic.
• Optimizing performance-critical UI and gesture interactions to reach 120fps and zero-latency feedback.
• Migrating legacy bridge-based React Native modules to the new architecture (Fabric/JSI).
• Implementing local AI features with privacy-first storage and vector search.
• Setting up modern Expo-based CI/CD and prebuild flows for reproducible native releases.

Best practices

• Treat performance as UX: push animation and gesture logic into worklets on the UI thread.
• Adopt JSI/TurboModules and Fabric; avoid JSON bridge calls for performance-sensitive code.
• Use Expo EAS and prebuilds to standardize builds and speed native development loops.
• Store secrets in secure enclaves/keychains or expo-secure-store; never keep sensitive data in AsyncStorage.
• Prefer StyleSheet.create and platform-specific UI refinements over inline styles.
• Use local vector DBs (SQLite VEC) for on-device intelligence and privacy-first search.

Example use cases

• Rewriting a high-interaction animation screen to use Reanimated 4 worklets and Fabric to eliminate jank.
• Migrating a large app from bridge modules to JSI/TurboModules to reduce latency and memory overhead.
• Building an offline-first assistant using local vector embeddings with secure storage for private user data.
• Standardizing builds across teams with Expo SDK 54 and EAS to reduce 'it works on my machine' issues.
• Delivering a Compose Multiplatform UI layer that shares business logic while preserving native look-and-feel.