Deploy Solidity Contracts

This guide covers deploying Solidity smart contracts on Rome EVM using Hardhat and Foundry.

Prerequisites

• Node.js v18+ (Hardhat) or Foundry installed

• A funded Rome EVM address (see Quickstart)

• Your private key exported as an environment variable

export PRIVATE_KEY="0xYOUR_PRIVATE_KEY"

Network Configuration

Network	RPC URL	Chain ID
Local	http://localhost:9090	1001
Devnet (montispl)	https://montispl.devnet.romeprotocol.xyz	200002
Testnet (Martius)	https://martius-i.testnet.romeprotocol.xyz	121214
Testnet (Caelian)	https://caelian-i.testnet.romeprotocol.xyz	121215

Hardhat

Setup

mkdir my-rome-project && cd my-rome-project
npm init -y
npm install --save-dev hardhat @nomicfoundation/hardhat-toolbox
npx hardhat init

hardhat.config.js

require("@nomicfoundation/hardhat-toolbox");

module.exports = {
  solidity: {
    version: "0.8.28",
    settings: {
      optimizer: { enabled: true, runs: 200 },
    },
  },
  networks: {
    rome_local: {
      url: "http://localhost:9090",
      chainId: 1001,
      accounts: [process.env.PRIVATE_KEY],
    },
    rome_devnet: {
      url: "https://montispl.devnet.romeprotocol.xyz",
      chainId: 200002,
      accounts: [process.env.PRIVATE_KEY],
    },
    rome_martius: {
      url: "https://martius-i.testnet.romeprotocol.xyz",
      chainId: 121214,
      accounts: [process.env.PRIVATE_KEY],
    },
    rome_caelian: {
      url: "https://caelian-i.testnet.romeprotocol.xyz",
      chainId: 121215,
      accounts: [process.env.PRIVATE_KEY],
    },
  },
};

Deploy

npx hardhat run scripts/deploy.js --network rome_devnet

Verify on Block Explorer

npx hardhat verify --network rome_martius 0xCONTRACT_ADDRESS

Foundry

Setup

forge init my-rome-project
cd my-rome-project

Deploy

# Local
forge create --rpc-url http://localhost:9090 \
  --private-key $PRIVATE_KEY \
  src/Counter.sol:Counter

# Devnet
forge create --rpc-url https://montispl.devnet.romeprotocol.xyz \
  --private-key $PRIVATE_KEY \
  src/Counter.sol:Counter

Call Deployed Contract

# Read
cast call 0xCONTRACT_ADDRESS "number()" \
  --rpc-url https://montispl.devnet.romeprotocol.xyz

# Write
cast send 0xCONTRACT_ADDRESS "increment()" \
  --rpc-url https://montispl.devnet.romeprotocol.xyz \
  --private-key $PRIVATE_KEY

Using the Rome Solidity SDK

For contracts that interact with Solana programs, install the Rome Solidity SDK:

npm install @rome-protocol/solidity-sdk

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.28;

import {SplToken, CpiProgram, SystemProgram} from "@rome-protocol/solidity-sdk/contracts/core/Precompiles.sol";
import {SPL_ERC20} from "@rome-protocol/solidity-sdk/contracts/token/ERC20SPL.sol";
import {RomeEVMAccount} from "@rome-protocol/solidity-sdk/contracts/core/RomeEVMAccount.sol";

contract MyRomeContract {
    // Read user's SPL token balance from Solana
    function getSolanaBalance(bytes32 mint) external view returns (uint64) {
        bytes32 userPda = RomeEVMAccount.pda(msg.sender);
        ISplToken.Account memory account = SplToken.account_state(userPda);
        return account.amount;
    }

    // Invoke any Solana program via CPI
    function callSolanaProgram(
        bytes32 programId,
        ICrossProgramInvocation.AccountMeta[] calldata accounts,
        bytes calldata data
    ) external {
        CpiProgram.invoke(programId, accounts, data);
    }
}

Deployment Constraints

Constraint	Limit	Notes
Max contract size	480 KB	Raised from Ethereum's 24 KB for OP-Geth mode
Transaction size limit	80 KB per holder	Large deploys are split across holder accounts transparently
Compute budget	~1.4M CU (atomic)	Use iterative mode for heavy contracts
Solidity version	0.8.28 recommended	Earlier versions work but 0.8.28 matches the SDK

Common Errors

Error	Cause	Fix
insufficient funds for gas	EVM address has no balance	Deposit SOL via the deposit UI
nonce too low	Stale nonce in wallet	Reset MetaMask account or specify nonce manually
execution reverted	Contract logic failed	Debug with eth_call or forge test --fork-url
transaction underpriced	Gas price below minimum	Increase gas price in transaction

What's Next

• Call Solana from EVM — use CPI precompiles to interact with Solana programs

• Token Wrapping — deploy ERC-20 wrappers for SPL tokens

• CU Optimization — reduce compute unit consumption