Monad REVM

Monad-revm extends the Revm implementation with Monad-specific customizations.

EVM Compatibility

Features

Gas Model

Monad uses a modified gas model optimized for its execution environment:

No Gas Refunds — Users pay gas_limit × gas_price, not gas_used × gas_price.

Increased Cold Access Costs — Cold storage reads are more expensive to reflect the cost of state access from disk:

Repriced Precompiles

Several precompiles are repriced to reflect their relative computational cost:

Additional Precompiles

Staking Precompile — monad-revm provides read-only access to Monad's native staking state at address 0x1000:

Bytecode Limits

Transaction Restrictions

Blob Transactions Rejected — EIP-4844 blob transactions return Eip4844NotSupported.

Installation

Add to your Cargo.toml:

[dependencies]
monad-revm = { git = "https://github.com/category-labs/monad-revm", branch = "main" }

Or from crates.io:

[dependencies]
monad-revm = "0.1"

Usage

Basic Example

use monad_revm::{MonadBuilder, DefaultMonad};
use revm::{
    context::{Context, TxEnv},
    database::InMemoryDB,
    ExecuteEvm,
};

// Create a Monad EVM context
let ctx = Context::monad();
let mut evm = ctx.build_monad();

// Execute a transaction
let tx = TxEnv::builder()
    .caller(caller_address)
    .to(contract_address)
    .value(U256::from(1000))
    .gas_limit(100_000)
    .gas_price(1_000_000_000)
    .build_fill();

let result = evm.transact(tx).expect("Transaction failed");

With Inspector

use monad_revm::{MonadBuilder, DefaultMonad};
use revm::{context::Context, inspector::NoOpInspector};

let ctx = Context::monad();
let mut evm = ctx.build_monad_with_inspector(NoOpInspector {});

With Custom Database

use monad_revm::{MonadBuilder, DefaultMonad};
use revm::context::Context;

let db = MyCustomDatabase::new();
let ctx = Context::monad().with_db(db);
let mut evm = ctx.build_monad();

Architecture

monad-revm/
├── crates/
│   └── monad-revm/
│       └── src/
│           ├── lib.rs           # Re-exports
│           ├── spec.rs          # MonadSpecId hardfork enum
│           ├── cfg.rs           # MonadCfgEnv 
│           ├── handler.rs       # MonadHandler
│           ├── instructions.rs  # Custom gas parameters
│           ├── precompiles.rs   # Repriced precompiles
│           ├── evm.rs           # MonadEvm type alias
│           ├── api/
│           │   ├── builder.rs   # MonadBuilder trait
│           │   ├── exec.rs      # MonadContextTr trait
│           │   └── default_ctx.rs # DefaultMonad extension
│           └── staking/
│               ├── mod.rs       # Staking precompile dispatcher
│               ├── abi.rs       # Gas constants
│               ├── interface.rs # Solidity ABI definitions
│               ├── storage.rs   # Storage slot calculations
│               └── types.rs     # Validator, Delegator, etc.
└── Cargo.toml

Key Components

MonadSpecId — Hardfork identifier. Currently only MonadEight (based on Prague).

MonadHandler — Implements Monad's gas model.

MonadPrecompiles — Provides repriced Ethereum precompiles plus P256VERIFY and the staking precompile.

monad_gas_params() — Returns gas parameters with Monad's cold access costs.

Feature Flags

• serde — Enable serialization for MonadSpecId
• alloy-evm — Enable integration with alloy_evm::precompiles::PrecompilesMap for Foundry/Anvil

Integration with Foundry

See monad-foundry for the complete Foundry integration.

Related Projects

• revm — Base Ethereum Virtual Machine
• alloy-monad-evm — Alloy EVM wrapper for monad-revm
• monad-foundry — Foundry fork with Monad support

References

• Monad Opcode Pricing
• Monad Precompiles
• Monad Changelog

License

Revm is licensed under MIT License.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in these crates by you, shall be licensed as above, without any additional terms or conditions.