Build Properties

The expo-build-properties plugin lets you configure native build settings for iOS and Android without writing custom config plugins. It’s the recommended way to set SDK versions, optimization flags, and other build properties.

Installation

Basic usage

Add the plugin to your app.json or app.config.js:

app.json

{
  "expo": {
    "plugins": [
      [
        "expo-build-properties",
        {
          "android": {
            "minSdkVersion": 24,
            "compileSdkVersion": 34,
            "targetSdkVersion": 34
          },
          "ios": {
            "deploymentTarget": "15.0"
          }
        }
      ]
    ]
  }
}

Android properties

SDK versions

Configure Android SDK versions:

{
  "android": {
    "minSdkVersion": 24,
    "compileSdkVersion": 34,
    "targetSdkVersion": 34,
    "buildToolsVersion": "34.0.0"
  }
}

From the source:

pluginConfig.ts

const EXPO_SDK_MINIMAL_SUPPORTED_VERSIONS = {
  android: {
    minSdkVersion: 21,
    compileSdkVersion: 31,
    targetSdkVersion: 31,
    kotlinVersion: '1.6.10',
  },
  ios: {
    deploymentTarget: '15.1',
  },
};

Kotlin version

Set the Kotlin version:

{
  "android": {
    "kotlinVersion": "1.9.0"
  }
}

Optimization settings

Enable code minification and resource shrinking:

{
  "android": {
    "enableMinifyInReleaseBuilds": true,
    "enableShrinkResourcesInReleaseBuilds": true,
    "enablePngCrunchInReleaseBuilds": true
  }
}

enableMinifyInReleaseBuilds - Enable R8 in release builds to obfuscate Java code and reduce app size. enableShrinkResourcesInReleaseBuilds - Enable shrinkResources to remove unused resources. Must be used with enableMinifyInReleaseBuilds. enablePngCrunchInReleaseBuilds (default: true) - Optimize PNG files. Disable if you do your own PNG optimization.

ProGuard rules

Add custom ProGuard rules:

{
  "android": {
    "extraProguardRules": "-keep class com.myapp.** { *; }\n-dontwarn okhttp3.**"
  }
}

Packaging options

Configure native library packaging:

{
  "android": {
    "packagingOptions": {
      "pickFirst": ["**/libc++_shared.so"],
      "exclude": ["META-INF/DEPENDENCIES"],
      "merge": ["META-INF/LICENSE"],
      "doNotStrip": ["**/libcrashlytics.so"]
    }
  }
}

From the types:

pluginConfig.ts

export interface PluginConfigTypeAndroidPackagingOptions {
  pickFirst?: string[];   // Only pack first occurrence
  exclude?: string[];     // Exclude from APK
  merge?: string[];       // Concatenate all occurrences
  doNotStrip?: string[];  // Keep debug symbols
}

Network configuration

Allow cleartext HTTP traffic:

{
  "android": {
    "usesCleartextTraffic": true
  }
}

For Android 8 and below, the default is true. For Android 9+, the default is false.

Maven repositories

Add custom Maven repositories:

{
  "android": {
    "extraMavenRepos": [
      "https://example.com/maven",
      {
        "url": "https://private.example.com/maven",
        "credentials": {
          "username": "user",
          "password": "System.getenv('MAVEN_PASSWORD')"
        },
        "authentication": "basic"
      }
    ]
  }
}

Supported authentication types:

basic - HTTP Basic authentication
digest - HTTP Digest authentication
header - Custom HTTP headers

Credential types:

pluginConfig.ts

export interface AndroidMavenRepositoryPasswordCredentials {
  username: string;
  password: string;
}

export interface AndroidMavenRepositoryHttpHeaderCredentials {
  name: string;
  value: string;
}

export interface AndroidMavenRepositoryAWSCredentials {
  accessKey: string;
  secretKey: string;
  sessionToken?: string;
}

Build architectures

Specify which ABIs to build:

{
  "android": {
    "buildArchs": ["arm64-v8a", "x86_64"]
  }
}

Default: ["armeabi-v7a", "arm64-v8a", "x86", "x86_64"] Building fewer architectures reduces app size but limits device compatibility.

Manifest queries

Specify apps your app intends to interact with (Android 11+):

{
  "android": {
    "manifestQueries": {
      "package": ["com.example.app"],
      "intent": [
        {
          "action": "android.intent.action.VIEW",
          "data": {
            "scheme": "https",
            "host": "example.com"
          }
        }
      ],
      "provider": ["com.example.provider"]
    }
  }
}

Legacy packaging

Use legacy native library packaging:

{
  "android": {
    "useLegacyPackaging": true
  }
}

Day/Night theme

Enable dark mode support:

{
  "android": {
    "useDayNightTheme": true
  }
}

Network Inspector

Control Network Inspector:

{
  "android": {
    "networkInspector": true
  }
}

Default: true

Bundle compression

Enable JavaScript bundle compression:

{
  "android": {
    "enableBundleCompression": true
  }
}

Results in smaller APK but may have slower startup.

Exclusive Maven mirror

Use a single Maven repository for all dependencies:

{
  "android": {
    "exclusiveMavenMirror": "https://maven.aliyun.com/repository/public"
  }
}

Useful for organizations with internal Maven mirrors.

iOS properties

Deployment target

Set minimum iOS version:

{
  "ios": {
    "deploymentTarget": "15.0"
  }
}

This affects:

CocoaPods projects
Xcode project build settings
All native targets

Use frameworks

Configure CocoaPods to use frameworks:

{
  "ios": {
    "useFrameworks": "static"
  }
}

Options:

"static" - Use static frameworks
"dynamic" - Use dynamic frameworks
undefined - Use default (static libraries)

This adds use_frameworks! :linkage => :static to Podfile.

Force static linking

Force specific pods to link statically:

{
  "ios": {
    "useFrameworks": "dynamic",
    "forceStaticLinking": [
      "React-Core",
      "React-RCTText"
    ]
  }
}

Useful when dynamic frameworks cause modular header issues.

Extra CocoaPods

Add additional CocoaPods:

{
  "ios": {
    "extraPods": [
      {
        "name": "Firebase/Analytics",
        "version": "~> 10.0.0"
      },
      {
        "name": "MyPod",
        "git": "https://github.com/example/MyPod.git",
        "tag": "1.0.0"
      }
    ]
  }
}

Full pod configuration:

pluginConfig.ts

export interface ExtraIosPodDependency {
  name: string;
  version?: string;           // e.g., "~> 1.0.0"
  configurations?: string[];  // e.g., ["Debug", "Release"]
  modular_headers?: boolean;
  source?: string;           // Custom CocoaPods spec repo
  path?: string;             // Local filesystem path
  podspec?: string;          // Custom podspec URL
  testspecs?: string[];      // Test specs to include
  git?: string;              // Git repository URL
  branch?: string;           // Git branch
  tag?: string;              // Git tag
  commit?: string;           // Git commit hash
}

Ccache

Enable C++ compiler cache:

{
  "ios": {
    "ccacheEnabled": true
  }
}

Speeds up C++ compilation by caching results.

Privacy manifest aggregation

Aggregate Privacy Manifests from CocoaPods:

{
  "ios": {
    "privacyManifestAggregationEnabled": true
  }
}

Merges all PrivacyInfo.xcprivacy files from pods into a single manifest.

Network Inspector

Control Network Inspector:

{
  "ios": {
    "networkInspector": true
  }
}

Default: true

Shared properties

These properties can be set at the top level or per-platform. Platform-specific values take precedence.

Build React Native from source

{
  "buildReactNativeFromSource": true,
  "ios": {
    "buildReactNativeFromSource": false  // Override for iOS
  }
}

From the source:

pluginConfig.ts

export function resolveConfigValue<K extends keyof SharedBuildConfigFields>(
  config: PluginConfigType,
  platform: 'android' | 'ios',
  key: K
): SharedBuildConfigFields[K] {
  return config[platform]?.[key] ?? config[key];
}

React Native release level

{
  "reactNativeReleaseLevel": "stable"
}

Options:

"stable" (default)
"canary"
"experimental"

Use Hermes V1

Enable experimental Hermes V1 engine:

{
  "useHermesV1": true,
  "buildReactNativeFromSource": true  // Required
}

From the validation:

pluginConfig.ts

if (androidUseHermesV1 === true && androidBuildFromSource !== true) {
  throw new Error(
    '`useHermesV1` requires `buildReactNativeFromSource` to be `true` for Android.'
  );
}

Complete configuration example

app.json

{
  "expo": {
    "plugins": [
      [
        "expo-build-properties",
        {
          "android": {
            "minSdkVersion": 24,
            "compileSdkVersion": 34,
            "targetSdkVersion": 34,
            "kotlinVersion": "1.9.0",
            "buildToolsVersion": "34.0.0",
            "enableMinifyInReleaseBuilds": true,
            "enableShrinkResourcesInReleaseBuilds": true,
            "extraProguardRules": "-keep class com.myapp.** { *; }",
            "packagingOptions": {
              "pickFirst": ["**/libc++_shared.so"]
            },
            "usesCleartextTraffic": false,
            "networkInspector": true,
            "extraMavenRepos": [
              "https://jitpack.io"
            ]
          },
          "ios": {
            "deploymentTarget": "15.0",
            "useFrameworks": "static",
            "ccacheEnabled": true,
            "privacyManifestAggregationEnabled": true,
            "networkInspector": true,
            "extraPods": [
              {
                "name": "Firebase/Analytics",
                "version": "~> 10.0.0"
              }
            ]
          },
          "buildReactNativeFromSource": false,
          "reactNativeReleaseLevel": "stable"
        }
      ]
    ]
  }
}

Validation

The plugin validates your configuration:

pluginConfig.ts

export function validateConfig(config: unknown, projectRoot?: string): PluginConfigType {
  validate(schema, config);
  maybeThrowInvalidVersions(config);
  
  if (
    config.android?.enableShrinkResourcesInReleaseBuilds === true &&
    config.android?.enableMinifyInReleaseBuilds !== true
  ) {
    throw new Error(
      '`android.enableShrinkResourcesInReleaseBuilds` requires ' +
      '`android.enableMinifyInReleaseBuilds` to be enabled.'
    );
  }
  
  // Additional validations...
  
  return config;
}

Using in custom plugins

Import types from expo-build-properties:

import type { PluginConfigType } from 'expo-build-properties/build/pluginConfig';
import { ConfigPlugin } from '@expo/config-plugins';

const withCustomBuildSettings: ConfigPlugin = (config) => {
  // Your build configuration logic
  return config;
};

Debugging

Enable debug output:

Best practices

1. Use minimal SDK versions

Don’t set SDK versions higher than necessary:

// Good: Supports most devices
{
  "android": {
    "minSdkVersion": 24
  }
}

// Avoid: Excludes many devices
{
  "android": {
    "minSdkVersion": 33
  }
}

2. Enable optimizations for release

{
  "android": {
    "enableMinifyInReleaseBuilds": true,
    "enableShrinkResourcesInReleaseBuilds": true
  }
}

3. Use environment variables for credentials

{
  "android": {
    "extraMavenRepos": [
      {
        "url": "https://private.example.com/maven",
        "credentials": {
          "username": "System.getenv('MAVEN_USERNAME')",
          "password": "System.getenv('MAVEN_PASSWORD')"
        }
      }
    ]
  }
}

4. Test build property changes

Always test after changing build properties:

5. Document custom settings

Add comments in app.config.js:

app.config.js

module.exports = {
  expo: {
    plugins: [
      [
        'expo-build-properties',
        {
          android: {
            // Using minSdk 24 for better device coverage
            minSdkVersion: 24,
            // Optimizations enabled for smaller APK
            enableMinifyInReleaseBuilds: true,
          },
        },
      ],
    ],
  },
};

Next steps

Modifying native projects - More native customization
iOS Entitlements - iOS capabilities
Android Permissions - Android permissions

Introduction

Building Plugins

Common Patterns

​Installation

​Basic usage

​Android properties

​SDK versions

​Kotlin version

​Optimization settings

​ProGuard rules

​Packaging options

​Network configuration

​Maven repositories

​Build architectures

​Manifest queries

​Legacy packaging

​Day/Night theme

​Network Inspector

​Bundle compression

​Exclusive Maven mirror

​iOS properties

​Deployment target

​Use frameworks

​Force static linking

​Extra CocoaPods

​Ccache

​Privacy manifest aggregation

​Network Inspector

​Shared properties

​Build React Native from source

​React Native release level

​Use Hermes V1

​Complete configuration example

​Validation

​Using in custom plugins

​Debugging

​Best practices

​1. Use minimal SDK versions

​2. Enable optimizations for release

​3. Use environment variables for credentials

​4. Test build property changes

​5. Document custom settings

​Next steps

Installation

Basic usage

Android properties

SDK versions

Kotlin version

Optimization settings

ProGuard rules

Packaging options

Network configuration

Maven repositories

Build architectures

Manifest queries

Legacy packaging

Day/Night theme

Network Inspector

Bundle compression

Exclusive Maven mirror

iOS properties

Deployment target

Use frameworks

Force static linking

Extra CocoaPods

Ccache

Privacy manifest aggregation

Network Inspector

Shared properties

Build React Native from source

React Native release level

Use Hermes V1

Complete configuration example

Validation

Using in custom plugins

Debugging

Best practices

1. Use minimal SDK versions

2. Enable optimizations for release

3. Use environment variables for credentials

4. Test build property changes

5. Document custom settings

Next steps