expo-build

name	expo-build
user-invocable	false
description	Use when building and deploying Expo apps with EAS Build. Covers build configuration, development builds, production builds, and app store submission.
allowed-tools	["Read","Write","Edit","Bash","Grep","Glob"]

Expo Build with EAS

Use this skill when building and deploying Expo applications using EAS (Expo Application Services) Build.

Key Concepts

EAS Build Configuration

// eas.json
{
  "cli": {
    "version": ">= 5.9.0"
  },
  "build": {
    "development": {
      "developmentClient": true,
      "distribution": "internal",
      "ios": {
        "simulator": true
      }
    },
    "preview": {
      "distribution": "internal"
    },
    "production": {
      "autoIncrement": true
    }
  },
  "submit": {
    "production": {}
  }
}

Build Commands

# Development build
eas build --profile development --platform ios
eas build --profile development --platform android

# Preview build
eas build --profile preview --platform all

# Production build
eas build --profile production --platform all

# Local build
eas build --profile production --platform ios --local

Development Builds

{
  "build": {
    "development": {
      "developmentClient": true,
      "distribution": "internal",
      "env": {
        "NODE_ENV": "development"
      }
    }
  }
}

Best Practices

Environment Variables

// eas.json
{
  "build": {
    "production": {
      "env": {
        "APP_ENV": "production",
        "API_URL": "https://api.myapp.com"
      }
    },
    "staging": {
      "env": {
        "APP_ENV": "staging",
        "API_URL": "https://staging-api.myapp.com"
      }
    }
  }
}

Secrets Management

# Set secrets
eas secret:create --scope project --name API_KEY --value your_api_key
eas secret:create --scope project --name GOOGLE_SERVICES_JSON --value "$(cat google-services.json)" --type file

# List secrets
eas secret:list

# Use in eas.json
{
  "build": {
    "production": {
      "env": {
        "API_KEY": "$(EAS_SECRET_API_KEY)"
      }
    }
  }
}

Version Management

// eas.json
{
  "build": {
    "production": {
      "autoIncrement": true,
      "ios": {
        "buildNumber": "1"
      },
      "android": {
        "versionCode": 1
      }
    }
  }
}

Build Hooks

{
  "build": {
    "production": {
      "prebuild": "npm run generate-assets",
      "postbuild": "npm run cleanup"
    }
  }
}

Common Patterns

Multi-Environment Builds

// eas.json
{
  "build": {
    "development": {
      "developmentClient": true,
      "channel": "development",
      "distribution": "internal"
    },
    "staging": {
      "channel": "staging",
      "distribution": "internal",
      "ios": {
        "bundleIdentifier": "com.myapp.staging"
      },
      "android": {
        "package": "com.myapp.staging"
      }
    },
    "production": {
      "channel": "production",
       
    
  

Custom Native Code

{
  "build": {
    "production": {
      "ios": {
        "buildConfiguration": "Release"
      },
      "android": {
        "gradleCommand": ":app:bundleRelease"
      }
    }
  }
}

App Store Submission

# iOS
eas submit --platform ios

# Android
eas submit --platform android

# Configure submission
# eas.json
{
  "submit": {
    "production": {
      "ios": {
        "appleId": "[e-mail]",
        "ascAppId": "1234567890",
        "appleTeamId": "AB12CD34EF"
      },
      "android": {
        "serviceAccountKeyPath": "./service-account.json",
        "track": "production"
      }
    }
  }
}

Build Monitoring

# View build status
eas build:list

# View specific build
eas build:view [build-id]

# Cancel build
eas build:cancel [build-id]

Anti-Patterns

Don't Commit Secrets

// Bad - Secrets in eas.json
{
  "build": {
    "production": {
      "env": {
        "API_KEY": "sk_live_1234567890"
      }
    }
  }
}

// Good - Use EAS Secrets
eas secret:create --scope project --name API_KEY --value sk_live_1234567890

Don't Skip Version Increments

// Bad - Manual version management
{
  "build": {
    "production": {
      "autoIncrement": false
    }
  }
}

// Good - Auto increment
{
  "build": {
    "production": {
      "autoIncrement": true
    }
  }
}

Related Skills

• expo-config: Configuring app for builds
• expo-updates: OTA updates after builds