Agent Skills: Skill: Expo Expert (Standard 2026)

Skill: Expo Expert (Standard 2026)

Role: The Expo Expert is the architect of modern, scalable mobile infrastructure. In 2026, Expo has moved completely to the Development Build paradigm, eliminating the need for "Ejecting." This skill focuses on the Expo Modules SDK, EAS (Expo Application Services), and leveraging native features while staying entirely within the managed-like workflow.

🎯 Primary Objectives

1. Modern Workflow Mastery: Utilizing expo-dev-client for custom native code without leaving the Expo ecosystem.
2. Native Module Engineering: Creating high-performance native bridges using the Expo Modules SDK (Swift/Kotlin).
3. EAS Orchestration: Managing CI/CD pipelines with EAS Build, Submit, and Update (OTA).
4. Local Intelligence: Implementing persistent storage with Expo SQLite and native file system management.

🏗️ The 2026 Expo Toolbelt

1. Core Services

• Expo SDK 55: Requiring the React Native New Architecture.
• Expo Router 4+: File-based routing with static typing and automatic deep linking.
• EAS Build: Cloud-based binary generation for iOS and Android.

2. Specialized SDKs

• Expo Modules SDK: The standard for writing modern native modules.
• Expo Image: High-fidelity image loading with blurhash support.
• Expo SQLite: Local database with full localStorage API support.

🛠️ Implementation Patterns

1. The Expo Module (Swift/Kotlin)

Writing native code in 2026 is done via the "DSL" approach, which is much safer and faster than the old Bridge.

// ios/MyModule.swift
import ExpoModulesCore

public class MyModule: Module {
  public function definition() -> ModuleDefinition {
    Name("MyModule")
    Function("hello") { (name: String) -> String in
      return "Hello \(name) from Native!"
    }
  }
}

2. Expo Router (File-based Navigation)

Automatic route generation based on the file system.

// app/user/[id].tsx
import { useLocalSearchParams } from 'expo-router';

export default function UserPage() {
  const { id } = useLocalSearchParams();
  return <Text>User ID: {id}</Text>;
}

3. EAS Update (OTA)

Deploying critical bug fixes in minutes without App Store review.

eas update --branch production --message "Fix: Hydration error in Checkout"

🚫 The "Do Not List" (Anti-Patterns)

1. NEVER "Eject" (npx expo prebuild is fine, but don't commit the ios/android folders unless strictly necessary).
2. NEVER use react-native-navigation if Expo Router fits the use case.
3. NEVER store large blobs in AsyncStorage. Use Expo SQLite or the File System.
4. NEVER perform heavy work in the app.json config. Use Config Plugins for complex native modifications.

🛠️ Troubleshooting & Infrastructure

| Issue | Likely Cause | 2026 Corrective Action | | :--- | :--- | :--- | | Native Module Missing | Using Go/Prebuilt Expo Go | Create a Development Build using eas build --profile development. | | Build Failure (EAS) | Missing Config Plugin for a library | Verify plugins in app.json and run npx expo prebuild locally to debug. | | Stale OTA Update | Caching in the update manifest | Use expo-updates API to force a re-check on app launch. | | Android Edge-to-Edge | System UI not compatible with SDK 55 | Use expo-system-ui to force consistent status bar behavior. |

📚 Reference Library

• Modern Expo Workflow: Development builds and Prebuild.
• Native Modules & Plugins: Extending the SDK.
• Local Data & Persistence: SQLite and File System.

📊 Quality Metrics

• Build Success Rate: > 95% on EAS.
• OTA Success Rate: > 99%.
• Native Crash Rate: < 0.1%.

🔄 Evolution from SDK 48 to 55

• SDK 50: Introduction of Dev Client by default.
• SDK 52: Expo Router becomes the standard.
• SDK 54: Precompiled RN for iOS, "Liquid Glass" support.
• SDK 55: Mandatory New Architecture, Predictive Back Gesture.

End of Expo Expert Standard (v1.1.0)