Epic Online Services (EOS)

Titan integrates with Epic Online Services for production authentication.

Overview

EOS Connect provides:

• Cross-platform identity
• Integration with Epic Games Store
• Player authentication without managing passwords

Configuration

Configure EOS in appsettings.json:

{
  "Eos": {
    "ClientId": "your-eos-client-id",
    "ClientSecret": "your-eos-client-secret",
    "DeploymentId": "your-deployment-id",
    "SandboxId": "your-sandbox-id"
  }
}

Setting	Description
ClientId	Your EOS application client ID
ClientSecret	Your EOS application secret
DeploymentId	EOS deployment identifier
SandboxId	EOS sandbox identifier

[!IMPORTANT] In production, EOS configuration is required. The API will fail to start if EOS options are missing.

Token Validation

EosConnectService validates tokens using OpenID Connect:

1. Fetches JWKS from EOS endpoints
2. Validates signature using public keys
3. Verifies claims (issuer, audience, expiration)
4. Extracts user ID from the sub claim

public class EosConnectService : IAuthService
{
    public async Task<AuthResult> ValidateTokenAsync(string token)
    {
        // Validate JWT signature and claims
        var validationResult = await ValidateJwtAsync(token);
        
        if (!validationResult.IsValid)
            return AuthResult.Failed("Invalid token");

        var productUserId = validationResult.Claims
            .First(c => c.Type == "sub").Value;

        return AuthResult.Success(
            Guid.Parse(productUserId),
            "EOS",
            ["Player"]
        );
    }
}

User ID Mapping

EOS provides a Product User ID (PUID) which becomes the Titan Account ID:

EOS Concept	Titan Equivalent
Product User ID	Account ID (Guid)
Display Name	User Profile
Platform Account	Linked Identity

Development Without EOS

For local development, use the Mock provider:

{
  "token": "mock:550e8400-e29b-41d4-a716-446655440000",
  "provider": "Mock"
}

The Mock provider:

• Accepts any GUID after mock:
• Only available in Development environment
• Does not validate with external services

if (builder.Environment.IsDevelopment())
{
    builder.Services.AddKeyedSingleton<IAuthService, MockAuthService>("Mock");
}

Unreal Engine Integration

In Unreal Engine, use the EOS SDK to get the ID token:

// Get EOS ID Token
EOS_Auth_Token* AuthToken = nullptr;
EOS_Auth_CopyIdToken(AuthHandle, &CopyOptions, &AuthToken);

// Login to Titan
FString Token = UTF8_TO_TCHAR(AuthToken->JsonWebToken);
TitanClient->Login(Token, "EOS");

See the Client SDK for the complete integration guide.

Troubleshooting

Token Validation Fails

1. Check EOS credentials - Verify ClientId and ClientSecret
2. Check token expiration - EOS tokens expire quickly
3. Verify deployment - Use correct DeploymentId for your environment

User Not Found

EOS Product User IDs are created on first login. Ensure:

1. User has linked their Epic account
2. EOS Connect is configured in your product