> ## Documentation Index
> Fetch the complete documentation index at: https://docs.crossmint.com/llms.txt
> Use this file to discover all available pages before exploring further.

# CrossmintClient

> Flutter Final Class

**Final Class**

Top-level facade for the Crossmint SDK.

```dart theme={null}
final class CrossmintClient
```

`CrossmintClient` owns every sub-client (`auth`, `wallets`, `credentials`,
`orders`, `tokens`, `users`), the shared transport, the auth session store,
and the hidden WebView signer bridge. All sub-clients share a closure that
reads the live JWT from `auth`, so token refresh works without rebuilding
the dependency graph.

## Lifecycle

1. Construct the client with a `CrossmintClientConfig`.
2. `await client.initialize()` — validates config and auto-resolves the app
   ID from platform metadata if not supplied.
3. `await client.auth.restoreSession()` — restores any persisted JWT.
4. Use sub-clients or factory helpers (`createWalletController`,
   `createEvmWallet`, etc.) for the rest of your session.
5. `await client.dispose()` when tearing down — shuts down the signer
   bridges and releases the auth client.

## Typical bootstrap

```dart theme={null}
final client = CrossmintClient(
  config: const CrossmintClientConfig(
    apiKey: 'YOUR_STAGING_API_KEY',
    appScheme: 'com.your.app',
  ),
);
await client.initialize();
await client.auth.restoreSession();

final walletController = client.createWalletController(
  const CrossmintWalletControllerConfig(showOtpSignerPrompt: true),
);
```

Named constructor parameters on the factory (`auth`, `wallets`, `transport`,
`runtimeOverrides`, etc.) are injection points primarily used by tests and
advanced integrations. Leave them null in production to get the default
HTTP transport, secure-storage-backed auth, and platform-resolved app ID.

## Constructors

### CrossmintClient

```dart theme={null}
factory CrossmintClient({
  required CrossmintClientConfig config,
  CrossmintAuthClient? auth,
  CrossmintWalletsClient? wallets,
  CrossmintCredentialsClient? credentials,
  CrossmintOrdersClient? orders,
  CrossmintTokensClient? tokens,
  CrossmintUsersClient? users,
  CrossmintTransport? transport,
  CrossmintAuthLauncher? authLauncher,
  CrossmintClientRuntimeOverrides? runtimeOverrides,
})
```

Creates a `CrossmintClient`.

## Properties

### config

```dart theme={null}
final CrossmintClientConfig config
```

The configuration this client was built with.

### auth

```dart theme={null}
final CrossmintAuthClient auth
```

Authentication sub-client — email OTP, OAuth, wallet sign-in, session persistence, JWT refresh.

### wallets

```dart theme={null}
final CrossmintWalletsClient wallets
```

Wallet sub-client — create, list, and read Crossmint-hosted wallets (EVM, Solana, Stellar) and their signers.

### credentials

```dart theme={null}
final CrossmintCredentialsClient credentials
```

Verifiable credentials sub-client — issue, query, and verify credentials.

### orders

```dart theme={null}
final CrossmintOrdersClient orders
```

Orders sub-client — checkout orders and mint/purchase flows.

### tokens

```dart theme={null}
final CrossmintTokensClient tokens
```

Tokens sub-client — metadata and balances for tokens held by wallets.

### users

```dart theme={null}
final CrossmintUsersClient users
```

Users sub-client — user profile lookups and updates.

### appId

```dart theme={null}
String? get appId
```

The effective app ID — explicit `CrossmintClientConfig.appId` if set, otherwise the value auto-resolved from platform metadata during `initialize`. May be `null` until `initialize` has completed.

### isInitialized

```dart theme={null}
bool get isInitialized
```

Whether `initialize` has completed successfully.

### isDisposed

```dart theme={null}
bool get isDisposed
```

Whether `dispose` has been called. Once disposed, the client cannot be reused — construct a new one.

### hiddenSignerBridgeController

```dart theme={null}
HiddenSignerBridgeRuntimeController get hiddenSignerBridgeController
```

The shared hidden signer bridge controller, lazily constructed on first access. Powers non-custodial email/phone signing inside a hidden WebView.

### authStorage

```dart theme={null}
CrossmintAuthStorage get authStorage
```

The auth storage adapter resolved during construction — either the one passed via `CrossmintClientConfig.authStorage` or the default `flutter_secure_storage`-backed implementation.

### transport

```dart theme={null}
CrossmintTransport get transport
```

The HTTP transport resolved during construction. Shared by every sub-client; injects the live JWT via a closure so token refresh works without rebuilding dependencies.

## Methods

### createWalletController

```dart theme={null}
CrossmintWalletController createWalletController(
  CrossmintWalletControllerConfig config,
)
```

Creates a `CrossmintWalletController` bound to this client.

### createHiddenSignerBridge

```dart theme={null}
HiddenSignerBridgeRuntimeController createHiddenSignerBridge({
  HiddenSignerBridgeConfig? config,
})
```

Builds a new `HiddenSignerBridgeRuntimeController` instance — used internally by `hiddenSignerBridgeController`. Override the bridge `config` to point at a custom signer URL (e.g. for testing).

### createExportSignerBridge

```dart theme={null}
CrossmintExportSignerBridgeRuntimeController createExportSignerBridge({
  HiddenSignerBridgeConfig? config,
})
```

Builds a new `CrossmintExportSignerBridgeRuntimeController` instance. Used internally by `exportSignerBridgeController`.

### createEvmNonCustodialSigner

```dart theme={null}
CrossmintEvmNonCustodialSigner createEvmNonCustodialSigner({
  required HiddenSignerBridge bridge,
  required String signerType,
  required String signerLocator,
  String? address,
  CrossmintSignerAuthRequiredCallback? onAuthRequired,
})
```

Builds a non-custodial EVM signer bound to an existing `HiddenSignerBridge`. Produces secp256k1 signatures inside the WebView without exposing keys to Dart.

### createSolanaNonCustodialSigner

```dart theme={null}
CrossmintSolanaNonCustodialSigner createSolanaNonCustodialSigner({
  required HiddenSignerBridge bridge,
  required String signerType,
  required String signerLocator,
  String? address,
  CrossmintSignerAuthRequiredCallback? onAuthRequired,
})
```

Builds a non-custodial Solana signer bound to an existing `HiddenSignerBridge`. Produces ed25519 signatures inside the WebView.

### createStellarNonCustodialSigner

```dart theme={null}
CrossmintStellarNonCustodialSigner createStellarNonCustodialSigner({
  required HiddenSignerBridge bridge,
  required String signerType,
  required String signerLocator,
  String? address,
  CrossmintSignerAuthRequiredCallback? onAuthRequired,
})
```

Builds a non-custodial Stellar signer bound to an existing `HiddenSignerBridge`. Produces ed25519 signatures inside the WebView.

### createEvmWallet

```dart theme={null}
CrossmintEvmWallet createEvmWallet({
  required CrossmintWallet wallet,
  CrossmintSignerConfig? recoverySigner,
  CrossmintWalletApprovalSigner? signer,
  List<CrossmintWalletApprovalSigner> additionalSigners =
      const <CrossmintWalletApprovalSigner>[],
  DeviceSignerKeyStorage? deviceSignerKeyStorage,
  CrossmintSignerAuthRequiredCallback? onAuthRequired,
})
```

Wraps a server-issued `CrossmintWallet` in a runtime `CrossmintEvmWallet`.

### createSolanaWallet

```dart theme={null}
CrossmintSolanaWallet createSolanaWallet({
  required CrossmintWallet wallet,
  CrossmintSignerConfig? recoverySigner,
  CrossmintWalletApprovalSigner? signer,
  List<CrossmintWalletApprovalSigner> additionalSigners =
      const <CrossmintWalletApprovalSigner>[],
  DeviceSignerKeyStorage? deviceSignerKeyStorage,
  CrossmintSignerAuthRequiredCallback? onAuthRequired,
})
```

Wraps a server-issued `CrossmintWallet` in a runtime `CrossmintSolanaWallet`.

### createStellarWallet

```dart theme={null}
CrossmintStellarWallet createStellarWallet({
  required CrossmintWallet wallet,
  CrossmintSignerConfig? recoverySigner,
  CrossmintWalletApprovalSigner? signer,
  List<CrossmintWalletApprovalSigner> additionalSigners =
      const <CrossmintWalletApprovalSigner>[],
  DeviceSignerKeyStorage? deviceSignerKeyStorage,
  CrossmintSignerAuthRequiredCallback? onAuthRequired,
})
```

Wraps a server-issued `CrossmintWallet` in a runtime `CrossmintStellarWallet`.

### createDeviceWalletSigner

```dart theme={null}
CrossmintDeviceWalletSigner createDeviceWalletSigner({
  required String signerLocator,
  required String address,
  DeviceSignerKeyStorage? storage,
})
```

Builds a hardware-backed device signer for an existing server signer.

### createEvmExternalWalletSigner

```dart theme={null}
CrossmintEvmExternalWalletSigner createEvmExternalWalletSigner({
  required String address,
  String? signerLocator,
  required CrossmintExternalWalletSignCallback onSign,
})
```

Builds an external-wallet EVM signer that delegates to a user-supplied `CrossmintExternalWalletSignCallback`. Use for wallets owned by the user (e.g. MetaMask, Rainbow) where the SDK only needs to request signatures.

### createSolanaExternalWalletSigner

```dart theme={null}
CrossmintSolanaExternalWalletSigner createSolanaExternalWalletSigner({
  required String address,
  String? signerLocator,
  required CrossmintExternalWalletSignCallback onSign,
})
```

Builds an external-wallet Solana signer that delegates to a user-supplied `CrossmintExternalWalletSignCallback`.

### createStellarExternalWalletSigner

```dart theme={null}
CrossmintStellarExternalWalletSigner createStellarExternalWalletSigner({
  required String address,
  String? signerLocator,
  required CrossmintExternalWalletSignCallback onSign,
})
```

Builds an external-wallet Stellar signer that delegates to a user-supplied `CrossmintExternalWalletSignCallback`.

### createPasskeyApprovalSigner

```dart theme={null}
CrossmintPasskeyApprovalSigner createPasskeyApprovalSigner({
  required String credentialId,
  required String signerLocator,
  required Future<CrossmintPasskeySignResult> Function(String message) onSign,
})
```

Builds a passkey approval signer. The caller provides `onSign` — a callback that performs the WebAuthn / platform-native passkey assertion and returns a `CrossmintPasskeySignResult`. Native platform passkey support is pending (Stage 2); today every passkey signer requires an explicit callback or `CrossmintSignerException(code: passkeyCallbackMissing)` is thrown during signing.

### dispose

```dart theme={null}
Future<void> dispose()
```

Releases the signer bridges and auth client, then marks the client as disposed. Safe to call multiple times. After disposal, construct a new `CrossmintClient` rather than reusing this one.

### initialize

```dart theme={null}
Future<void> initialize()
```

Validates configuration and prepares the client for use.