Flutter (Mobile)

This guide walks you through the setup of Para in a Flutter application. You’ll learn how to install the SDK, configure iOS/Android for passkey-based logins, implement user authentication flows, and generate wallets.

If you haven’t already created your Flutter app, follow the official Flutter docs to set up a new project.

Prerequisites

To use Para, you need an API key. This key authenticates your requests to Para services and is essential for integration.

Don’t have an API key yet? Request access to the Developer Portal to create API keys, manage billing, teams, and more.

Installation

Start by installing the Para SDK:

flutter pub add para

Project Setup

To set up associated domains for passkey functionality in your Flutter project, you need to configure both iOS and Android platforms:

To enable passkeys on iOS, you need to set up associated domains in your Xcode project:

Open your Flutter project’s iOS folder in Xcode
Select your target and go to “Signing & Capabilities”
Click ”+ Capability” and add “Associated Domains”
Add the following domains:
- webcredentials:app.beta.usecapsule.com
- webcredentials:app.usecapsule.com

For more details, see the Apple Developer documentation.

Important: You must register your TeamId and BundleId with Para via the Developer Portal to use associated domains. This is required by Apple for passkey security. Allow up to 24 hours for domain propagation.

To enable passkeys on iOS, you need to set up associated domains in your Xcode project:

Open your Flutter project’s iOS folder in Xcode
Select your target and go to “Signing & Capabilities”
Click ”+ Capability” and add “Associated Domains”
Add the following domains:
- webcredentials:app.beta.usecapsule.com
- webcredentials:app.usecapsule.com

For more details, see the Apple Developer documentation.

For Android setup, you need to provide your app’s SHA-256 certificate fingerprint to Para.

Quick Testing Option: You can use com.getpara.example.flutter as your package name for immediate testing. This package name is pre-registered and works with the SHA-256 certificate from the default debug.keystore, making it testable in debug mode for newly scaffolded Flutter apps.

Fix Namespace Issue

For newer versions of Flutter, you need to add the following configuration block to your android/build.gradle file to resolve a namespace issue with the passkey dependency:

subprojects {
    afterEvaluate { project ->
        if (project.hasProperty('android')) {
            project.android {
                if (namespace == null) {
                    namespace project.group
                }
            }
        }
    }
}

Get SHA-256 Fingerprint

To get your SHA-256 fingerprint:

For debug builds: keytool -list -v -keystore ~/.android/debug.keystore
For release builds: keytool -list -v -keystore <your_keystore_path>

For production apps, you’ll need to: 1. Upgrade your plan in the Developer Portal 2. Register your actual package name 3. Provide your app’s SHA-256 fingerprint 4. Wait up to 24 hours for the Digital Asset Links to propagate

To ensure passkey functionality works correctly:

Enable biometric or device unlock settings (fingerprint, face unlock, or PIN)
Sign in to a Google account on the device (required for Google Play Services passkey management)

Initializing Para

To use Para’s features, you’ll need to initialize a Para client instance that can be accessed throughout your app. This client handles all interactions with Para’s services, including authentication, wallet management, and transaction signing.

Create a file (e.g., lib/services/para_client.dart) to initialize your Para client:

import 'package:para/para.dart';

// Initialize a global Para client instance
final para = Para(
  environment: Environment.beta, // Use Environment.prod for production
  apiKey: 'YOUR_PARA_API_KEY',
);

You can access para from anywhere in your app by importing the file where you initialized it. This singleton pattern ensures consistent state management across your application.

Para offers two hosted environments: Environment.BETA (alias Environment.DEVELOPMENT) for testing, and Environment.PROD (alias Environment.PRODUCTION) for live use. Select the environment that matches your current development phase.

Using the Para SDK

The Para SDK provides multiple authentication methods including email and phone. Here’s how to implement these methods in your Flutter application.

Beta Testing Credentials In the BETA Environment, you can use any email ending in @test.getpara.com (like dev@test.getpara.com) or US phone numbers (+1) in the format (area code)-555-xxxx (like (425)-555-1234). Any OTP code will work for verification with these test credentials. These credentials are for beta testing only. You can delete test users anytime in the beta developer console to free up user slots.

Create a User with Email

Follow these steps to register a new user with email verification:

Future<void> registerUser(String email) async {
  // Check if user exists
  if (await para.checkIfUserExists(email)) {
    // User exists, handle login flow
    return;
  }
  
  // Create a new user account - this sends a verification code
  await para.createUser(email);
  
  // Next step: Verify the email with the code
}

Future<void> verifyAndCreateWallet(String email, String verificationCode) async {
  // Verify the code to get biometricsId
  final biometricsId = await para.verifyEmail(verificationCode);
  
  // Generate a passkey for this device
  await para.generatePasskey(email, biometricsId);
  
  // Create a wallet for the user
  final result = await para.createWallet(skipDistribute: false);
  
  // Store the recovery share securely
  final recoveryShare = result.recoveryShare;
}

To authenticate an existing user with their email:

Future<void> loginUser() async {
  // This triggers the platform's native passkey selection UI
  final wallet = await para.login();
  
  // User is now logged in
  // You can access their wallet address
  final address = wallet.address;
}

You can also check if a user is already logged in:

Future<void> checkLoginStatus() async {
  final isLoggedIn = await para.isFullyLoggedIn();
  
  if (isLoggedIn) {
    // User is logged in, get their wallets
    final wallets = await para.getWallets();
    
    // Access the first wallet
    if (wallets.isNotEmpty) {
      final wallet = wallets.values.first;
      final address = wallet.address;
    }
  }
}

Create a User with Email

Follow these steps to register a new user with email verification:

Future<void> registerUser(String email) async {
  // Check if user exists
  if (await para.checkIfUserExists(email)) {
    // User exists, handle login flow
    return;
  }
  
  // Create a new user account - this sends a verification code
  await para.createUser(email);
  
  // Next step: Verify the email with the code
}

Future<void> verifyAndCreateWallet(String email, String verificationCode) async {
  // Verify the code to get biometricsId
  final biometricsId = await para.verifyEmail(verificationCode);
  
  // Generate a passkey for this device
  await para.generatePasskey(email, biometricsId);
  
  // Create a wallet for the user
  final result = await para.createWallet(skipDistribute: false);
  
  // Store the recovery share securely
  final recoveryShare = result.recoveryShare;
}

To authenticate an existing user with their email:

Future<void> loginUser() async {
  // This triggers the platform's native passkey selection UI
  final wallet = await para.login();
  
  // User is now logged in
  // You can access their wallet address
  final address = wallet.address;
}

You can also check if a user is already logged in:

Future<void> checkLoginStatus() async {
  final isLoggedIn = await para.isFullyLoggedIn();
  
  if (isLoggedIn) {
    // User is logged in, get their wallets
    final wallets = await para.getWallets();
    
    // Access the first wallet
    if (wallets.isNotEmpty) {
      final wallet = wallets.values.first;
      final address = wallet.address;
    }
  }
}

Create a User with Phone

Follow these steps to register a new user with phone verification:

Future<void> registerUserByPhone(String phone, String countryCode) async {
  // Check if user exists
  if (await para.checkIfUserExistsByPhone(phone, countryCode)) {
    // User exists, handle login flow
    return;
  }
  
  // Create a new user account - this sends an SMS verification code
  await para.createUserByPhone(phone, countryCode);
  
  // Next step: Verify the phone with the code
}

Future<void> verifyPhoneAndCreateWallet(String phone, String countryCode, String verificationCode) async {
  // Verify the code to get biometricsId
  final biometricsId = await para.verifyPhone(verificationCode);
  
  // Generate a passkey for this device
  // The full phone number format should be: +{countryCode}{phone}
  final fullPhoneNumber = '+$countryCode$phone';
  await para.generatePasskey(fullPhoneNumber, biometricsId);
  
  // Create a wallet for the user
  final result = await para.createWallet(skipDistribute: false);
  
  // Store the recovery share securely
  final recoveryShare = result.recoveryShare;
}

Phone numbers need to be in the format +1234567890 with the country code included. For country code ensure a + is included.

To authenticate an existing user with their phone number:

Future<void> loginUserByPhone() async {
  // This triggers the platform's native passkey selection UI
  final wallet = await para.login();
  
  // User is now logged in
  // You can access their wallet address
  final address = wallet.address;
}

Resend Verification Code

If the user doesn’t receive the verification code:

Future<void> resendVerificationCode() async {
  await para.resendVerificationCodeByPhone();
}

When createWallet is called with skipDistribute: false, Para automatically handles the distribution of backup shares. Make sure to securely store and display the recovery secret to the user in your app as it’s essential for account recovery.

Working with Wallets

Once a user is authenticated, you can access and manage their wallets:

// Get all wallets for the current user
Future<void> getUserWallets() async {
  try {
    final wallets = await para.getWallets();
    
    // Access wallet information
    for (final wallet in wallets) {
      print('Wallet type: ${wallet.type}');
      print('Wallet address: ${wallet.address}');
    }
  } catch (e) {
    // Handle errors
  }
}

Examples

For practical implementations of the Para SDK in Flutter environments, check out our GitHub repository:

Flutter Integration Examples

Explore our repository containing Flutter implementations, along with shared UI components demonstrating Para integration.

Troubleshooting

If you encounter issues during the integration or usage of the Para SDK in your Flutter application, here are some common problems and their solutions:

Para SDK initialization fails

Passkey operations fail or throw errors

Authentication fails or API requests are rejected

Flutter platform-specific issues

Next Steps

After integrating Para into your Flutter app, you can explore other features and integrations to enhance your Para experience.

EVM Integration

Learn how to use Para as a signer for signing EVM transactions

Solana Integration

Discover how to use Para as a signer for signing Solana transactions

Cosmos Integration

Explore using Para as a signer for Cosmos transactions.

Introduction

Setup

Guides

API & Troubleshooting

Flutter (Mobile)

Prerequisites

Installation

Project Setup

Fix Namespace Issue

Get SHA-256 Fingerprint

Initializing Para

Using the Para SDK

Create a User with Email

Create a User with Email

Create a User with Phone

Resend Verification Code

Working with Wallets

Examples

Flutter Integration Examples

Troubleshooting

Next Steps

EVM Integration

Solana Integration

Cosmos Integration

Introduction

Setup

Guides

API & Troubleshooting

​Prerequisites

​Installation

​Project Setup

​Fix Namespace Issue

​Get SHA-256 Fingerprint

​Initializing Para

​Using the Para SDK

​Create a User with Email

​Login with Email

​Create a User with Email

​Login with Email

​Create a User with Phone

​Login with Phone

​Resend Verification Code

​Working with Wallets

​Examples

Flutter Integration Examples

​Troubleshooting

​Next Steps

EVM Integration

Solana Integration

Cosmos Integration

Prerequisites

Installation

Project Setup

Fix Namespace Issue

Get SHA-256 Fingerprint

Initializing Para

Using the Para SDK

Create a User with Email

Login with Email

Create a User with Email

Login with Email

Create a User with Phone

Login with Phone

Resend Verification Code

Working with Wallets

Examples

Troubleshooting

Next Steps