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Game Bridge Architecture

Learn how Immutable game SDKs work internally and how to adapt them for custom engines.

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Overview

The Unity and Unreal SDKs share a common architecture that bridges native game engines with TypeScript-based functionality. This design allows consistent behavior across platforms while leveraging platform-specific capabilities. The architecture has three main components: a game bridge for communication, an invisible WebView for executing TypeScript, and an in-app browser for secure authentication.

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Architecture Diagrams

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High-Level Architecture

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Communication Flow

How the game engine communicates with TypeScript SDK packages through JSON serialization:

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PKCE Authentication Flow

How authentication works using in-app browsers for security:

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Core Components

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1. Game Bridge

The game bridge enables string-based communication between your game engine and the TypeScript SDK. How it works:

• The game-bridge package enables communication with TypeScript SDK packages
• TypeScript packages are bundled into a single file loaded into an invisible WebView
• The game SDK sends JSON string messages to the WebView and receives responses

Implementation:

• Unity: index.html
• Unreal: index.js

Both contain the bundled TypeScript SDK and game-bridge package.

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2. WebView

An invisible WebView loads the game bridge and executes TypeScript SDK functionality. Requirements:

• HTML/JavaScript loading support
• Modern JavaScript (ES6+)
• Bidirectional native-JavaScript communication
• Hidden from user view (no UI rendering)

Platform considerations:

• Mobile: Native WebView components (Android/iOS)
• Desktop: May require embedded browser frameworks
• Windows: CEF 90+ required

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3. In-App Browser

Authentication uses an in-app browser (not WebView) for security and SSO compatibility. Requirements:

• Secure, isolated browser context
• Process isolation (runs separately from your app)
• Deep link callback handling
• System authentication session support

For platform-specific implementations, see:

• Unity SDK Repository
• Unreal SDK Repository

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Adapting for Custom Engines

To adapt the SDK for your custom engine, you’ll need to modify three areas:

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1. Modify the Game Bridge

Keep the bundled TypeScript SDK but modify the callbackToGame() function in game-bridge/index.ts to communicate with your engine. After modification, rebuild the bundle following the game-bridge README.

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2. Implement WebView Communication

Option A: Reuse our platform-native WebView implementations and adapt the communication layer Option B: Implement a custom WebView with bidirectional string communication and lifecycle management Reference implementation:

• C# engines: Unity SDK
• C++ engines: Unreal SDK

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3. Implement PKCE Authentication

Reuse our platform-native PKCE implementations and deep linking handlers. Adapt the communication layer between your engine and native code for URL scheme registration and callback handling.

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Related Documentation