Unreal SDK — Getting Started

Skill — Download

This guide shows the minimum setup to run OAuth login and wallet actions with the CROSSx Unreal SDK.

Requirements

Unreal Engine 5.x
C++ project (Blueprint-only projects need a C++ shim)

1) Install the Plugin

Copy the CROSSxSdkUnrealPlugin folder into your project's Plugins/ directory:

YourProject/
├── Plugins/
│   └── CROSSxSdkUnrealPlugin/
│       ├── CROSSxSdkUnrealPlugin.uplugin
│       └── Source/
└── Source/

Add the module to your project's .Build.cs:

PublicDependencyModuleNames.AddRange(new string[] {
    "CROSSxSdkUnrealPlugin"
});

2) Configure deep link callback

OAuth completes in a native browser and redirects back using a custom URI scheme: crossx-{ProjectId}.

Windows

Registry entries are handled by the SDK's deep link adapter. For manual setup, add a registry key:

HKCU\Software\Classes\crossx-YOUR_PROJECT_ID\shell\open\command

Android

Add an intent filter in your AndroidManifest.xml:

<activity android:name="com.epicgames.unreal.GameActivity"
          android:exported="true"
          android:launchMode="singleTask">
    <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="crossx-YOUR_PROJECT_ID" />
    </intent-filter>
</activity>

iOS

3) Configure the SDK

The SDK is accessed via UCROSSxSdkSubsystem, a UGameInstanceSubsystem.

UCROSSxSdkSubsystem* Sdk = GetGameInstance()->GetSubsystem<UCROSSxSdkSubsystem>();

FCROSSxSdkConfig Config;
Config.ProjectId = TEXT("YOUR_PROJECT_ID");
Config.AppId = TEXT("com.example.myapp");
Config.AppName = TEXT("My Game");
Config.Environment = ECROSSxSdkEnvironment::Development; // resolves URLs automatically
Config.Theme = ECROSSxThemeMode::Dark;

Sdk->Configure(Config);

Environment-based URL resolution

Environment	OAuth Server	Auth API	Gateway
Development	`dev-cross-wallet-oauth.crosstoken.io`	`dev-cross-auth.crosstoken.io`	`dev-embedded-wallet-gateway.crosstoken.io/api/v1`
Staging	`stg-cross-wallet-oauth.crosstoken.io`	`stg-cross-auth.crosstoken.io`	`stg-embedded-wallet-gateway.crosstoken.io/api/v1`
Production	`cross-wallet-oauth.crosstoken.io`	`cross-auth.crosstoken.io`	`embedded-wallet-gateway.crosstoken.io/api/v1`
Custom	Set `OAuthServerUrl`, `AuthApiUrl`, `EmbeddedWalletGatewayUrl` manually

4) Initialize and enable confirmation UI

FCROSSxAuthResult AuthResult = Sdk->InitializeSdk();
if (AuthResult.bSuccess)
{
    UE_LOG(LogTemp, Log, TEXT("Session restored: %s"), *AuthResult.WalletAddress);
}

Sdk->EnableSignConfirmation(TEXT("My Game"), ECROSSxThemeMode::Dark);

5) Basic auth flow

// Synchronous
FCROSSxAuthResult Auth = Sdk->SignIn(ECROSSxLoginProvider::Google);

// Asynchronous
Sdk->SignInAsync(ECROSSxLoginProvider::Google,
    FCROSSxAuthResultDelegate::CreateLambda([](const FCROSSxAuthResult& Result)
    {
        UE_LOG(LogTemp, Log, TEXT("SignIn %s"), Result.bSuccess ? TEXT("OK") : TEXT("FAIL"));
    })
);

// Sign out
Sdk->SignOut();

6) Basic wallet flow

FString ChainId = TEXT("eip155:612044");

FCROSSxGetAddressResponse Addr = Sdk->GetAddress();
FString Balance = Sdk->GetBalance(Addr.Address, ChainId);