Flutter SDK API

Para Class

The Para class is the main entry point for the Para Flutter SDK, providing wallet operations, authentication, and blockchain interactions. The latest version includes passkey authentication, comprehensive multi-chain support, and deep linking capabilities.

Constructor

Creates a new Para SDK instance using the configuration factory constructor.

Hide Parameters

ParaConfig

required

Configuration object containing environment and API key.

String

required

Your app’s deep link scheme (e.g., “yourapp”).

final para = Para.fromConfig(
  config: ParaConfig(
    environment: Environment.beta,
    apiKey: 'YOUR_API_KEY',
    jsBridgeUri: Uri.parse('custom-bridge-url'), // Optional
    relyingPartyId: 'custom.domain.com',         // Optional
  ),
  appScheme: 'yourapp',
);

Authentication Methods

Future<AuthState>

Initiates authentication flow for email or phone. Returns an AuthState indicating next steps.

Hide Parameters

Auth

required

Authentication object using Auth.email() or Auth.phone() helper methods.

// Email authentication
final authState = await para.initiateAuthFlow(
  auth: Auth.email('user@example.com')
);

// Phone authentication
final authState = await para.initiateAuthFlow(
  auth: Auth.phone('+1234567890')
);

Future<AuthState>

Verifies the OTP code sent to email/phone during authentication.

Hide Parameters

String

required

The 6-digit OTP verification code.

final verifiedState = await para.verifyOtp(
  otp: '123456'
);

Handles login for existing users with passkey authentication.

Hide Parameters

AuthState

required

The auth state returned from initiateAuthFlow() for existing users.

final wallet = await para.handleLogin(
  authState: authState,
);

Handles the complete signup flow for new users, including passkey creation and wallet setup.

Hide Parameters

AuthState

required

The auth state returned from verifyOtp() for new users.

SignupMethod

required

The signup method to use: SignupMethod.passkey.

final wallet = await para.handleSignup(
  authState: authState,
  method: SignupMethod.passkey,
);

Future<AuthState>

Handles complete OAuth authentication flow using an external browser.

Hide Parameters

OAuthMethod

required

OAuth provider: OAuthMethod.google, .twitter, .apple, .discord, or .facebook.

String

required

Your app’s deep link scheme for OAuth callback (e.g., ‘yourapp’).

final authState = await para.verifyOAuth(
  provider: OAuthMethod.google,
  appScheme: 'yourapp',
);

Wallet Management

ParaFuture<Wallet>

Creates a new wallet with enhanced multi-chain support. Returns a ParaFuture that can be cancelled.

Hide Parameters

WalletType

The type of wallet to create: WalletType.evm, .solana, or .cosmos (default: WalletType.evm).

bool

required

Whether to skip the distributed backup process.

final walletFuture = para.createWallet(
  type: WalletType.evm,
  skipDistribute: false,
);

final wallet = await walletFuture.future;
// Or cancel: await para.cancelOperationById(walletFuture.requestId);

ParaFuture<List<Wallet>>

Retrieves all wallets for the current user.

final walletsFuture = para.fetchWallets();
final wallets = await walletsFuture.future;

Signing Operations

ParaFuture<SignatureResult>

Signs a message with the specified wallet. Returns a cancellable ParaFuture.

Hide Parameters

String

required

The wallet ID to use for signing.

String

required

The message to sign, base64-encoded.

int?

Optional timeout in milliseconds (default: 30000).

String?

For Cosmos signing: The SignDoc as base64-encoded JSON. When provided, this method signs a Cosmos transaction instead of a generic message.

// Generic message signing
final signatureFuture = para.signMessage(
  walletId: wallet.id,
  messageBase64: base64Encode(utf8.encode('Hello, Para!')),
);

final signature = await signatureFuture.future;

// Cosmos transaction signing
final cosmosSignature = await para.signMessage(
  walletId: cosmosWallet.id,
  messageBase64: '', // Not used for Cosmos
  cosmosSignDocBase64: base64Encode(utf8.encode(jsonEncode(signDoc))),
).future;

ParaFuture<SignatureResult>

Signs an EVM transaction. Returns a cancellable ParaFuture.

This method is for EVM transactions only. For Solana, use signMessage() with the serialized transaction as messageBase64. For Cosmos, use signMessage() with cosmosSignDocBase64.EVM Transaction Return Value: The SuccessfulSignatureResult contains the complete RLP-encoded transaction ready for broadcasting via the signedTransaction property.Solana/Cosmos Return Value: For pre-serialized transactions, returns just the signature in signedTransaction. For constructed transactions, returns the complete signed transaction.

Hide Parameters

String

required

The wallet ID to use for signing.

String

required

RLP-encoded EVM transaction (base64).

String

required

Chain ID of the EVM network.

int?

Optional timeout in milliseconds (default: 30000).

// EVM transaction signing
final signatureFuture = para.signTransaction(
  walletId: evmWallet.id,
  rlpEncodedTxBase64: base64Encode(rlpEncodedTx),
  chainId: '1', // Ethereum mainnet
);

final signature = await signatureFuture.future;

Future<void>

Cancels an ongoing operation by its request ID.

Hide Parameters

String

required

The request ID from a ParaFuture.

final signatureFuture = para.signMessage(...);
// Cancel the operation
await para.cancelOperationById(signatureFuture.requestId);

Session Management

ParaFuture<bool>

Checks if there’s an active user session.

final isActive = await para.isSessionActive();

ParaFuture<String>

Exports the current session as an encrypted string.

final sessionData = await para.exportSession();
// Save sessionData securely

ParaFuture<void>

Logs out the current user and clears session data.

await para.logout();

Utility Methods

ParaFuture<ParaUser>

Gets the current user’s basic profile and session status.

final user = await para.currentUser();
if (user.isLoggedIn) {
  debugPrint('Logged in as ${user.userId}');
}

Returns a browser URL for One-Click (BASIC_LOGIN) authentication.

Hide Parameters

String

required

bool?

Request a shortened URL.

final loginUrl = await para.getLoginUrl(authMethod: 'BASIC_LOGIN');

Future<Uri?>

Presents an auth URL in a secure system web view and returns the callback URI (if any).

Hide Parameters

String

required

The authentication URL to open.

ParaWebAuthenticationSession

required

Platform-specific web authentication session.

String

Descriptive label for logging (default: authentication).

bool

Whether to preload signing keyshares after completion.

final callback = await para.presentAuthUrl(
  url: loginUrl,
  webAuthenticationSession: webAuthSession,
  context: 'One-Click login',
  loadTransmissionKeyshares: true,
);

Waits for an ongoing login operation to complete.

Hide Parameters

Function()?

Optional function to check if operation is canceled.

int

Polling interval in milliseconds (default: 2000).

final result = await para.waitForLogin(pollingIntervalMs: 1000);

Polls for completion of a pending One-Click signup.

Hide Parameters

int?

Optional timeout in milliseconds (default: no timeout).

final completed = await para.waitForSignup(timeoutMs: 300000);

ParaFuture<Map<String, dynamic>>

Waits for wallet creation to complete after signup.

Hide Parameters

Function()?

Optional function to check if operation is canceled.

int

Polling interval in milliseconds (default: 2000).

final result = await para.waitForWalletCreation(pollingIntervalMs: 1000);

ParaFuture<Map<String, dynamic>?>

Refreshes the current session metadata and returns the latest snapshot (or null if nothing changed).

final snapshot = await para.touchSession();
if (snapshot != null) {
  debugPrint('Session touched at ${snapshot['updatedAt']}');
}

String?

Formats a phone number for authentication.

Hide Parameters

String

required

The phone number to format.

String

required

The country code (e.g., ‘1’ for US, ‘44’ for UK).

final formatted = para.formatPhoneNumber('1234567890', '1');
// Returns: '+11234567890' (exact format depends on implementation)

ParaFuture<bool>

Checks if the current user is using an external wallet.

final isExternal = await para.isUsingExternalWallet();

ParaFuture<void>

Clears local storage data.

Hide Parameters

bool

required

Whether to keep the Paillier secret key (default: false).

await para.clearStorage(false);

void

Disposes of SDK resources. Call when the SDK is no longer needed.

para.dispose();

Extension Methods

Para provides extension methods for cleaner authentication flows (requires importing extensions):

import 'package:para/src/auth_extensions.dart';

ParaAuthExtensions

Future<AuthState>

Initiates authentication and returns the current state using Auth helper class.

Hide Parameters

Auth

required

Authentication method: Auth.email() or Auth.phone().

// Must import extensions
import 'package:para/src/auth_extensions.dart';

final authState = await para.initiateAuthFlow(
  auth: Auth.email('user@example.com')
);

Future<Uri?>

Presents a password authentication URL in a secure web view.

Hide Parameters

String

required

The password authentication URL.

WebAuthenticationSession

required

Web authentication session for handling the flow.

Types and Enums

Environment

enum Environment {
  dev,      // Development environment
  beta,     // Beta environment
  prod      // Production environment
}

Auth

class Auth {
  static AuthEmail email(String email);
  static AuthPhone phone(String phoneNumber);
}

AuthState

class AuthState {
  final AuthStage stage;           // Current authentication stage
  final String? userId;            // User's unique identifier
  final AuthIdentity auth;         // Authentication identity details
  final String? displayName;       // User's display name
  final String? pfpUrl;           // Profile picture URL
  final String? username;         // Username
  final Map<String, dynamic>? externalWallet; // External wallet info
  final String? loginUrl;         // One-Click URL, when provided
  final List<String>? loginAuthMethods;   // Advertised login methods (e.g., BASIC_LOGIN)
  final List<String>? signupAuthMethods;  // Advertised signup methods
  final String? passkeyUrl;       // URL for passkey authentication
  final String? passkeyId;        // Passkey identifier
  final String? passwordUrl;      // URL for password authentication
  final AuthStage? nextStage;     // Optional next stage hint

  // Helper getters exposed by the SDK:
  bool get hasSloUrl;             // loginUrl is non-empty
  List<String> get loginMethods;  // loginAuthMethods ?? []
  List<String> get signupMethods; // signupAuthMethods ?? []
  AuthStage get effectiveNextStage; // nextStage ?? stage
}

class AuthIdentity {
  final String? email;
  final String? phoneNumber;
  final String? fid;              // Farcaster ID
  final String? telegramUserId;
  // Other identity types
}

enum AuthStage {
  verify,  // Need to verify email/phone
  login,   // Existing user, proceed to login
  signup   // New user, proceed to signup
}

SignupMethod

enum SignupMethod {
  passkey,  // Hardware-backed passkey
  password  // Password-based authentication
}

OAuthMethod

enum OAuthMethod {
  google,
  twitter,
  apple,
  discord,
  facebook
}

WalletType

enum WalletType {
  evm,     // Ethereum and EVM-compatible chains
  solana,  // Solana blockchain
  cosmos   // Cosmos-based chains
}

ParaFuture

class ParaFuture<T> {
  final Future<T> future;    // The actual future
  final String requestId;    // ID for cancellation
}

Wallet

class Wallet {
  final String id;
  final String address;
  final WalletType type;
  final WalletScheme scheme;
  final String? userId;         // Associated user ID
  final DateTime? createdAt;    // Creation timestamp
  final String? publicKey;      // Wallet public key
  final bool? isPregen;         // Whether this is a pregenerated wallet
  // Additional optional fields available
}

SignatureResult

// Abstract base class
abstract class SignatureResult {}

// Successful signature
class SuccessfulSignatureResult extends SignatureResult {
  final String signedTransaction;  // For transactions: complete signed transaction ready for broadcasting
                                   // For messages: just the signature

  SuccessfulSignatureResult(this.signedTransaction);

  /// Gets the transaction data ready for broadcasting.
  String get transactionData => signedTransaction;
}

// Denied signature
class DeniedSignatureResult extends SignatureResult {
  final String? pendingTransactionId;
  DeniedSignatureResult(this.pendingTransactionId);
}

// Denied with URL
class DeniedSignatureResultWithUrl extends SignatureResult {
  final String? pendingTransactionId;
  final String url;
  DeniedSignatureResultWithUrl({this.pendingTransactionId, required this.url});
}

Get Started

Set Up Project

Add Authentication

Build Wallet UI

Transact on Chains

Manage Sessions

Add Advanced Features

Debug and Launch

Para Class

Constructor

Authentication Methods

Wallet Management

Signing Operations

Session Management

Utility Methods

Extension Methods

ParaAuthExtensions

Types and Enums

Environment

Auth

AuthState

SignupMethod

OAuthMethod

WalletType

ParaFuture

Wallet

SignatureResult

​Para Class

​Constructor

​Authentication Methods

​Wallet Management

​Signing Operations

​Session Management

​Utility Methods

​Extension Methods

​ParaAuthExtensions

​Types and Enums

​Environment

​Auth

​AuthState

​SignupMethod

​OAuthMethod

​WalletType

​ParaFuture

​Wallet

​SignatureResult

Para Class

Constructor

Authentication Methods

Wallet Management

Signing Operations

Session Management

Utility Methods

Extension Methods

ParaAuthExtensions

Types and Enums

Environment

Auth

AuthState

SignupMethod

OAuthMethod

WalletType

ParaFuture

Wallet

SignatureResult