Configure Expo Apps with app.json and app.config.js

Expo Config Setup Expert transforms Claude into an expert at configuring Expo projects via app.json, app.config.js, and platform-specific settings for development and production builds, with deep knowledge of Expo SDK features, platform-specific configuration, build settings, and deployment optimization. Core principles: use app.json for static config that doesn't change between environments and app.config.js for dynamic config needing environment variables or conditional logic, never put sensitive data directly in config files, use environment variables instead, and always configure both iOS and Android platforms explicitly with platform-specific overrides for permissions, capabilities, and UI guidelines.

Use it when setting up or hardening an Expo project's configuration: the core app.config.js structure covering name, slug, version, icon, splash, and iOS, Android, and web blocks; environment-specific configuration that switches app name, slug, scheme, and extra/EAS project settings based on a dev, preview, or production variant; EAS Build profiles in eas.json; plugin configuration for expo-camera, expo-location, expo-notifications, and async-storage with permission strings; comprehensive icon and splash asset configuration per platform and density; and deep-linking and scheme setup including iOS associated domains and Android intent filters. It is specific to Expo and React Native project configuration, not general React Native code or native module development.

Input is an Expo project's configuration requirements - target platforms, environment variants, plugins needed, and deep-linking or asset requirements. Output is app.config.js/app.json configuration code, eas.json build-profile definitions, plugin configuration arrays with permission descriptions, platform-specific icon and splash asset blocks including Android density variants, and deep-linking configuration for scheme, associated domains, and intent filters.

// eas.json
{
  "cli": {
    "version": ">= 3.0.0"
  },
  "build": {
    "development": {
      "developmentClient": true,
      "distribution": "internal",
      "env": {
        "APP_VARIANT": "development"
      }
    },
    "preview": {
      "distribution": "internal",
      "env": {
        "APP_VARIANT": "preview"
      }
    },
    "production": {
      "env": {
        "APP_VARIANT": "production"
      }
    }
  },
  "submit": {
    "production": {}
  }
}

Documented Expo plugins include expo-font, expo-camera, expo-location, expo-notifications, and @react-native-async-storage/async-storage, each configured with its own permission-string options. EAS-specific integration covers EAS Build profiles, EAS Update URLs keyed to a project ID, and EAS Secrets for sensitive build-time variables, alongside metro.config.js for bundle tree-shaking and expo doctor for configuration validation.

React Native developers configuring an Expo project for multi-environment builds, EAS Build and Update, deep linking, or native permissions who want a documented app.config.js/eas.json structure and common pitfalls to avoid, rather than assembling Expo configuration from scratch.