MUD Introduction

MUD is a framework for ambitious Ethereum applications. It compresses the complexity of building EVM apps with a tightly integrated software stack.

MUD evolved out of our experiences building onchain games like Dark Forest (opens in a new tab) and zkDungeon. We identified many difficulties along the way: coupling of state and logic in smart contracts makes upgrading logic difficult, lack of synchrony between the chain and client can lead to inconsistencies in game state, irregularities with access controls pose problems for would-be third-party developers attempting to create their own plugins and clients. This revealed the need for a framework and a protocol to handle the inevitable complexity of game code, and to counteract the developer-unfriendly patterns inherent in the way smart contracts are traditionally written. We built MUD with solutions to these problems in mind.

The projects built with MUD speak for themselves: some of the most complex applications on Ethereum have been built with the framework in record time. OPCraft, a fully onchain voxel world, was built by Lattice in 1.5 months. While it didn’t have the security and auditing requirement of financial applications, it handled more transaction throughput than most apps on Mainnet ever did in their lifetime: in 10 days, OPCraft players made 3.5 million transactions, filling the MUD onchain database with billions of gas worth of storage; with the client seamlessly handling synchronizing that state back. OPCraft used MUD without any additional tricks: large onchain applications with minimal client headaches can be yours too!

MUD is maximally onchain: the entire application state lives in the EVM, and the only requirement for clients and frontends is an Ethereum Node. You can use all MUD libraries together as a framework and get super-powers, or only pick the parts you like. It’s up to you!


MUD is open-source software licensed as MIT (opens in a new tab).