Step-by-Step Guide: Building Composable Gameplay in MUD and Dojo Frameworks

Composable gameplay is rapidly becoming the cornerstone of modern on-chain games, enabling developers to create modular, reusable mechanics that can be combined in novel ways. As blockchain gaming matures, frameworks like MUD and Dojo are at the forefront, offering robust toolsets for building interoperable, fully on-chain experiences. In this guide, we’ll break down the essential steps to architecting composable gameplay using these two leading frameworks, and examine why their shared Entity-Component-System (ECS) architecture is a game changer for decentralization and scalability.

Why Composable Gameplay Matters in On-Chain Games

Traditional game development often locks mechanics into rigid silos, making it difficult to extend or remix features. Fully on-chain games built with composable architectures flip this paradigm by emphasizing modularity: each game mechanic is a discrete component or system that can be reused or upgraded without rewriting core logic. This approach enables:

• Rapid iteration: developers can test new mechanics by swapping out components.
• User-driven innovation: players and third-party developers can extend games permissionlessly.
• On-chain interoperability: game assets and logic interact seamlessly across titles built on the same framework.

The result? A fertile ecosystem where creativity compounds, and value accrues not just to original creators but to anyone who builds atop the shared infrastructure.

ECS Architecture: The Backbone of Modularity

Both MUD and Dojo leverage the ECS pattern, a proven model from traditional game development now adapted for Web3. Here’s how it breaks down:

• Entities: Unique identifiers (e. g. , player characters, items) with no intrinsic data.
• Components: Data containers (like health points or inventory) attached to entities.
• Systems: Logic modules that operate on entities with specific components (for example, a combat system affecting all entities with health and attack power).

This separation of data from logic makes it trivial to add new features or overhaul existing ones without breaking compatibility, a crucial advantage for evolving on-chain worlds.

MUD Framework: Step-by-Step Guide to Composable Gameplay

MUD provides a streamlined environment for building autonomous worlds on Ethereum-compatible chains. Its focus on composability covers everything from data storage to frontend synchronization. Here’s how to get started:

Getting Started: Setting Up a MUD Project and Deploying Contracts

Initialize Your MUD Project

Begin by setting up your development environment. Use the MUD framework’s project generator to scaffold your project. This ensures all dependencies and configurations are correctly established for onchain game development.

Define Game Components

Create components to represent the data aspects of your game entities. In MUD, components are modular pieces of data (like health, position, or inventory) that can be attached to entities. This modularity allows for flexible and scalable gameplay design.

Implement Systems for Game Logic

Develop systems that contain the logic to manipulate your components. Systems operate on entities with specific components and define the rules and interactions within your game. For example, a movement system updates position components based on player actions.

Deploy Smart Contracts to Testnet

Once components and systems are defined, deploy your contracts to an Ethereum testnet. Use the MUD client tools to interact with your contracts, test gameplay mechanics, and verify that your systems function as intended.

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You’ll begin by installing the framework using pnpm create mud@latest, then define your components, such as player stats or item attributes, in TypeScript or Solidity. Systems encapsulate your core gameplay logic; for instance, a trading system might handle swaps between player inventories. Once your contracts are written and deployed to a testnet, you can interact via the MUD client interface. For hands-on learning, consider following the detailed walkthrough in the Emojimon tutorial.

Building with Dojo: Modular Games on Starknet

If you’re targeting Starknet’s high-throughput L2 environment, Dojo offers a Cairo-based ECS implementation designed for provable games and autonomous worlds. The workflow mirrors MUD but adapts key elements for Starknet’s architecture:

Initializing a Dojo Project with Cairo Structs and Contract Systems

Install Dojo and Set Up Your Environment

Begin by installing the Dojo framework and its dependencies. Follow the official Dojo Getting Started documentation to ensure your development environment is correctly configured. This typically includes installing Cairo, Dojo CLI, and any required toolchains for Starknet development.

Define Components as Cairo Structs

Model your game’s data by creating Cairo structs. These structs act as ECS components, representing attributes like health, position, or inventory for your game entities. Place these definitions in the appropriate components directory within your Dojo project.

Implement Systems as Contract Functions

Develop the logic of your game by writing contract functions that operate on your Cairo structs. These systems are responsible for manipulating component data, such as moving entities or updating scores. Organize these functions in the systems directory.

Configure System Permissions

Set up authorization rules for your contract systems to control which entities or users can execute specific actions. Proper permissions ensure secure and intended interactions within your game world.

Register Components and Systems in the Dojo World

Integrate your components and systems by registering them within the Dojo world. This step connects your data models and logic, making them accessible and composable in the game environment.

Build and Test Your Client Application

Leverage Dojo’s indexed data to develop a client application, such as a web or Unity-based frontend. Test interactions with your deployed contracts to ensure components and systems work as intended.

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You’ll define models as Cairo structs representing your entity data (e. g. , position or inventory), then implement systems as contract functions operating over these models. Permissions are configurable at the system level, crucial for securing gameplay logic while allowing extensibility. Models and systems are registered within your “world” smart contract so they’re discoverable by clients and other contracts. For more detail, consult the official Getting Started with Dojo guide.