For AI agents: a documentation index is available at /llms.txt. A markdown version of this page is available at the same URL with .md appended (or via Accept: text/markdown).
Skip to main content

Embedded Wallets SDK for Flutter

Overview​

MetaMask Embedded Wallets SDK (formerly Web3Auth Plug and Play) provides social login authentication for Flutter applications. The Flutter SDK, written in Dart, helps you manage authentication state across both iOS and Android platforms. After sign-in, export the private key and use platform-native blockchain libraries such as web3dart or solana.

Requirements​

  • Android API version 26 or newer, with compileSdkVersion 34
  • iOS 14 or newer, Xcode 15+ and Swift 5.9+, with Swift Package Manager enabled in Flutter
  • Basic knowledge of Dart and Flutter Development

Prerequisites​

tip

See the dashboard setup guide to learn more.

Installation​

To install the Web3Auth Flutter package, you have two options. You can either manually add the package in the pubspec.yaml file, or you can use the flutter pub add command.

Add via pubspec.yaml​

Add web3auth_flutter as a dependency to your pubspec.yaml:

dependencies:
  web3auth_flutter: ^8.0.0

Add via Flutter pub add​

Add web3auth_flutter using flutter pub add command:

flutter pub add web3auth_flutter

1. Android configuration​

Once we have installed Web3Auth Flutter SDK, we also need to add the configuration for Android.

Update compileSdkVersion​

For Android build compileSdkVersion needs to be 34. Check your app module Gradle file in your project to change it:

android {
    namespace "com.example.app_name"
    compileSdkVersion 34
   // ..
}

Add Embedded Wallets to Gradle​

In your project-level Gradle file add JitPack repository:

dependencyResolutionManagement {
    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
    repositories {
        google()
        mavenCentral()
        maven { url "https://jitpack.io" } // <-- Add this line
    }
}

Update permissions​

Open your app's AndroidManifest.xml file and add the following permission. Please make sure the <uses-permission> element should be a direct child of the <manifest> root element:

<uses-permission android:name="android.permission.INTERNET" />

Open your app's AndroidManifest.xml file and add the following deep link intent filter to your Main activity:

<intent-filter>
  <action android:name="android.intent.action.VIEW" />

  <category android:name="android.intent.category.DEFAULT" />
  <category android:name="android.intent.category.BROWSABLE" />

  <data android:scheme="{scheme}" android:host="{YOUR_APP_PACKAGE_NAME}"/>
  <!-- Accept URIs: w3a://com.example.w3aflutter -->
</intent-filter>

Handle custom tabs​

For Android, you need to handle custom tabs lifecycle to trigger login exceptions. The Android SDK uses chrome custom tabs, and it's not possible to add a listener directly to the chrome custom tab close button to trigger login exceptions.

class LoginScreen extends StatefulWidget {
  @override
  _LoginScreenState createState() => _LoginScreenState();
}

class _LoginScreenState extends State<LoginScreen> with WidgetsBindingObserver {
  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addObserver(this);
  }

  @override
  void dispose() {
    super.dispose();
    WidgetsBinding.instance.removeObserver(this);
  }

  @override
  void didChangeAppLifecycleState(final AppLifecycleState state) {
    // This is important to trigger the user cancellation on Android.
    if (state == AppLifecycleState.resumed) {
      Web3AuthFlutter.setCustomTabsClosed();
    }
  }
}

2. iOS configuration​

Update global iOS platform​

For iOS build global platform needs to be 14.0 or later. Check Podfile in your project to change the global platform:

platform :ios, '14.0'

Enable Swift Package Manager​

Starting with v8, web3auth_flutter resolves the native Web3Auth Swift SDK (v13) through Swift Package Manager. The plugin's podspec no longer declares a CocoaPods Web3Auth dependency, so iOS builds fail unless Swift Package Manager is enabled for your Flutter project:

flutter config --enable-swift-package-manager

After enabling it, run flutter clean and rebuild. Flutter adds the generated Swift package to your Xcode project automatically. See the Flutter Swift Package Manager guide for details.

3. Configure redirects​

  • From the Embedded Wallets dashboard, create or open an existing Web3Auth project.
  • For iOS, allowlist {bundleId}://auth in the dashboard. This step is mandatory for the redirect to work.

Initialize Web3Auth​

1. Configure Web3Auth instance​

Import and configure Web3Auth in your Flutter application:

main.dart
import 'package:web3auth_flutter/web3auth_flutter.dart';
import 'package:web3auth_flutter/enums.dart';
import 'package:web3auth_flutter/input.dart';
import 'package:web3auth_flutter/output.dart';
import 'dart:io';

Future<void> initWeb3Auth() async {
  late final String redirectUrl;

  if (Platform.isAndroid) {
    redirectUrl = 'w3a://com.example.w3aflutter';
    // w3a://com.example.w3aflutter
  } else {
    redirectUrl = 'com.example.w3aflutter://auth';
    // com.example.w3aflutter://auth
  }

  await Web3AuthFlutter.init(Web3AuthOptions(
    clientId: "YOUR_WEB3AUTH_CLIENT_ID", // Pass your Web3Auth Client ID, ideally using an environment variable // Get your Client ID from Embedded Wallets dashboard
    web3AuthNetwork: Web3AuthNetwork.sapphire_mainnet, // or Web3AuthNetwork.sapphire_devnet
    redirectUrl: redirectUrl,
    authBuildEnv: BuildEnv.production,
  ));
}

2. Initialize an Embedded Wallets instance​

Initialize the Embedded Wallets instance and check for existing sessions:

class _MyAppState extends State<MyApp> with WidgetsBindingObserver {
  String _result = '';
  bool logoutVisible = false;

  @override
  void initState() {
    super.initState();
    initPlatformState();
  }

  Future<void> initPlatformState() async {
    await initWeb3Auth();

    try {
      // Restore an existing session. Throws when no active session is present.
      await Web3AuthFlutter.initialize();
    } catch (e) {
      print('No active session: $e');
    }

    final privateKey = await Web3AuthFlutter.getPrivateKey();
    if (privateKey.isNotEmpty) {
      setState(() {
        logoutVisible = true;
        _result = 'Existing session found';
      });
    }
  }
}
note

After configuring Embedded Wallets with init, call the initialize method to restore an existing session. On Android, initialize also fetches your project configuration from the dashboard. On iOS, init restores the session and initialize verifies that an authenticated session exists.

initialize throws when no active session is present (for example, on first launch or after logout), or when the project configuration request fails. Wrap it in a try/catch block and treat the error as "user isn't signed in".

Advanced configuration​

The Embedded Wallets Flutter SDK offers a rich set of advanced configuration options:

tip

See the advanced configuration sections to learn more about each configuration option.

await Web3AuthFlutter.init(Web3AuthOptions(
  clientId: "YOUR_WEB3AUTH_CLIENT_ID", // Pass your Web3Auth Client ID, ideally using an environment variable
  web3AuthNetwork: Web3AuthNetwork.sapphire_mainnet, // or Web3AuthNetwork.sapphire_devnet
  redirectUrl: redirectUrl,
));

Blockchain integration​

Web3Auth is blockchain agnostic, enabling integration with any blockchain network. Out of the box, Web3Auth offers robust support for both Solana and Ethereum.

Ethereum integration​

For Ethereum integration, you can get the private key and use it with web3dart or other Ethereum libraries:

import 'package:web3dart/web3dart.dart';

// Use your Web3Auth instance to get the private key
final privateKey = await Web3AuthFlutter.getPrivateKey();

// Generate the Credentials
final credentials = EthPrivateKey.fromHex(privateKey);

// Get the address
final address = credentials.address;

// Create the Web3Client instance using your RPC URL
final client = Web3Client("YOUR_RPC_URL", Client());

// Get the balance
final balanceResponse = await client.getBalance(address);

// Convert the balance to ether format, and round off to 4 decimal places.
final balance = balanceResponse.getValueInUnit(EtherUnit.ether).toStringAsFixed(4);

Solana integration​

For Solana integration, you can get the Ed25519 private key:

import 'dart:math';
import 'package:solana/solana.dart';
import 'package:web3auth_flutter/web3auth_flutter.dart';

// Use your Web3Auth instance to get the ED25519 private key
final privateKey = await Web3AuthFlutter.getEd25519PrivateKey();

// Generate the KeyPair
final keyPair = await Ed25519HDKeyPair.fromPrivateKeyBytes(
  privateKey: privateKey,
);

// Get the address
final address = keyPair.address;

// Create the SolanaClient instance using Solana RPC URL
final client = SolanaClient(
  rpcUrl: Uri.parse('https://api.devnet.solana.com'),
  websocketUrl: Uri.parse('ws://api.devnet.solana.com'),
);

// Get the balance
final balanceResponse = await client.rpcClient.getBalance(address);

// Convert the balance from lamports to SOL, and round off to 4 decimal places
final balance = (balanceResponse.value / pow(10, 9)).toStringAsFixed(4);

On this page