Mud

MUD began as a response to real-world challenges faced while building onchain games like Dark Forest and zkDungeon. These early projects highlighted how difficult it was to manage onchain state, maintain upgradability, and synchronize game logic between blockchain and frontend. This inspired the creation of a new kind of engine — one that would not only manage storage efficiently but also unify the entire development stack from contract to client.

Unlike traditional EVM development, which often requires separate efforts to build contracts, write indexers, and sync frontend apps, MUD offers a holistic development framework. It provides a familiar relational data model via its custom Store engine, allowing developers to define data schemas and interact with them like they would with a database. Events are automatically emitted and indexed, enabling real-time state reflection without additional infrastructure.

The World component acts as the access-controlled logic layer above Store. It enables permissioned or permissionless System contracts to extend a shared onchain world, similar to plug-ins or facets in the Diamond standard — but with built-in support for namespaces and third-party extensions. Systems can interact across namespaces, creating truly modular applications while still retaining fine-grained access control.

MUD has been adopted by both independent developers and full-scale studios. Projects like Biomes, Words3, Dappmon, and PopCraft were built using MUD’s architecture. The framework's modularity and efficiency have also made it ideal for complex simulations, high-frequency games, and onchain infrastructure tools.

With over 30+ live projects and a fast-evolving open-source ecosystem, MUD is setting the standard for what it means to build maximally onchain apps. It competes with tools like Foundry, Hardhat, and Ethers.js, but goes much further by unifying the entire lifecycle of development, deployment, and user interaction into one composable system.

MUD provides a set of advanced features that redefines what’s possible when building Ethereum applications:

• Integrated Software Stack: Combines storage, logic, indexing, and frontend syncing in one framework with no glue code required.
• Relational Data Model on Ethereum: The Store engine models data as typed tables and records, supporting familiar developer workflows.
• Automatic Indexing: Events are emitted on every change, allowing clients to stay in sync with onchain state in real time without writing custom indexers.
• World-Based Access Control: A centralized logic entry point ensures secure execution while enabling extensibility through permissionless namespaces.
• Maximally Onchain Applications: The full application state resides on the EVM — no separate backends or middleware required.
• Built-in Developer Tools: Features like hot reloading, modular templates, and support for ERC-4337 bundlers reduce development friction.
• Production Ready: Used by games and applications handling millions of transactions, such as OPCraft’s 3.5M+ interactions in 10 days.
• Open Source and Extensible: Fully open under the MIT license, with a thriving contributor base and actively maintained core modules.

MUD is easy to get started with, thanks to its flexible templates and comprehensive documentation:

• Step 1 – Install Dependencies: Ensure you have Node.js v20, pnpm v8+, Git, and optionally Foundry installed.
• Step 2 – Create a New Project: Run pnpm create mud@latest to scaffold a new MUD project using one of the available templates like Vanilla, React, or Three.js.
• Step 3 – Choose Your Template: During setup, select from multiple frontend options like React-ECS, Phaser, or Three.js to customize how your world will be visualized.
• Step 4 – Start Development Server: Use pnpm dev to spin up the dev environment with automatic contract hot-reloading and synchronized client updates.
• Step 5 – Explore the Architecture: Your project will include two main packages: contracts (onchain logic) and client (offchain UI). Make changes in either to extend your world.
• Step 6 – Deploy on EVM Chains: Use Quarry or your preferred ERC-4337 compatible bundler to deploy your world with ultra-low latency.