created_at2024-06-03 13:54:03.847782
updated_at2024-06-18 14:15:12.355135
descriptionDeploy Stylus contracts with Solidity constructors
Alexander González (alexfertel)




koba (工場)

Generate deployment transaction data for Stylus contracts.

[!WARNING] This project is still in a very early and experimental phase. It has never been audited nor thoroughly reviewed for security vulnerabilities. Do not use in production.

This project is meant to be temporary. The problem it solves should be fixed by either cargo-stylus itself or in the Stylus VM. As such, we maintain this on a best-effort basis.


Deployment transactions in Ethereum are composed of three sections:

  • A prelude - The bytecode prefix whose execution gets triggered by the deployment transaction.
  • A runtime - The bytecode of the smart contract stored on-chain.
  • Constructor arguments - ABI-encoded arguments received by the constructor.

Deployment transactions with an input of only compressed wasm are not yet supported in Stylus. That is, only the runtime is actual webassembly.

Moreover, the prelude of deployment transactions using cargo-stylus is hard-coded.

koba allows using a Solidity constructor alongside Stylus contracts, enabling users to deploy their code in a familiar way.

koba can be used both as a CLI tool or as a library in Rust projects. For a usage example beyond the section below, check out OpenZeppelin Contracts for Stylus.


To install koba on your machine, just run:

cargo install koba

Compiling Solidity code with koba requires solc to be installed and available through the command line.

You can also use koba as a library by adding it to your project using cargo add koba.


You can use the command-line interface in two ways: the generate and the deploy commands.

koba generate

For a contract like this:

sol_storage! {
    pub struct Counter {
        uint256 number;

impl Counter {
    pub fn number(&self) -> U256 {

    pub fn increment(&mut self) {
        let number = self.number.get();
        self.set_number(number + U256::from(1));

With a constructor like this:

contract Counter {
    uint256 private _number;

    constructor() {
        _number = 5;

the following command outputs the transaction data you would need to send to deploy the contract.

$ koba generate --sol <path-to-constructor> --wasm <path-to-wasm>

You can then use cast for example to deploy and activate the contract, like this:

# Deploy the contract.
cast send --rpc-url https://stylusv2.arbitrum.io/rpc --private-key <private-key> --create <koba output>

# Activate the contract.
cast send --rpc-url https://stylusv2.arbitrum.io/rpc --private-key <private-key> --value "0.0001ether" 0x0000000000000000000000000000000000000071 "activateProgram(address)(uint16,uint256)" <contract address>

# Interact with the contract
cast call --rpc-url https://stylusv2.arbitrum.io/rpc <contract address> "number()"

cast send --rpc-url https://stylusv2.arbitrum.io/rpc --private-key <private-key> <contract address> "increment()"

cast storage --rpc-url https://stylusv2.arbitrum.io/rpc <contract address> 0

koba deploy

For the same code in the above section, you can instead just run koba deploy with the appropriate arguments to deploy and activate your Stylus contract in one go:

$ koba deploy --sol <path-to-constructor> --wasm <path-to-wasm> --args <constructor-arguments> -e https://stylusv2.arbitrum.io/rpc --private-key <private-key>
wasm data fee: Ξ0.000113
init code size: 20.8 KB
deploying to RPC: https://stylusv2.arbitrum.io/rpc
deployed code: 0x470AE56DFbea924722423926782D8aB30f108A49
deployment tx hash: 0xb52a68b973fb883dbef6bf3e0cbee4f02608ae71ad5a89f6a2f0c9f094242a5b
activated with 2987042 gas
activation tx hash: 0x40086445e80365b648621fd62d978d716708fe05144f303baa620086eda854d1


  • immutable variables - koba currently does not support Solidity's immutable variables, since there is no equivalent mechanism for Stylus.
  • MCOPY - Version 0.8.24 of Solidity introduced the MCOPY opcode from EIP-5656. As of 2024-05-28, nitro-testnode does not support this opcode.

Why koba

koba means factory in Japanese -- the factory where a stylus gets assembled.

Commit count: 30

cargo fmt