OpenZeppelin Contracts for Stylus

A secure, modular smart contract library for Arbitrum Stylus, written in Rust and inspired by OpenZeppelin Contracts.

Stylus enables high-performance smart contracts in Rust, compiled to WebAssembly (Wasm), for deployment on Arbitrum chains.

✨ Features

• Security-first contracts, ported from the openzeppelin-contracts library.
• Full support for no_std Rust environments.
• Ready-to-use unit and integration testing helpers, used in our own tests.
• Familiar, well-documented contract APIs.

🚀 Usage

Add the crate to your Cargo.toml:

[dependencies]
# We recommend pinning to a specific version.
openzeppelin-stylus = "=0.2.0"

If you want to use the latest features before they are fully stabilized or audited, try the most recent alpha. We release a new alpha version every ~3 weeks.

[dependencies]
openzeppelin-stylus = "=0.3.0-alpha.1"

Enable ABI export support:

[features]
# stylus-sdk/export-abi will be enabled automatically.
export-abi = ["openzeppelin-stylus/export-abi"]

🧱 no_std Projects

This library is designed for no_std environments to reduce Wasm size. Ensure your dependencies also avoid the standard library:

[dependencies]
alloy-primitives = { version = "=0.8.20", default-features = false }
stylus-sdk = "=0.9.0"

🦀 Rust Nightly & WASM Builds

This library requires the Rust nightly toolchain, due to unstable flags used during compilation to reduce the Wasm size of Stylus contracts.

⚠️ Note: While nightly is pinned in this repository via rust-toolchain.toml, this only affects local development within this repo.
We also include a config.toml to define platform-specific compiler flags.

End-users of the crate must set their own nightly toolchain when compiling projects that use openzeppelin-stylus.

To compile contracts for Arbitrum Stylus, run:

cargo build --release --target wasm32-unknown-unknown \
  -Z build-std=std,panic_abort \
  -Z build-std-features=panic_immediate_abort

🧪 Example: ERC20 Token

Once defined as a dependency, use one of our pre-defined implementations by importing them:

use openzeppelin_stylus::token::erc20::{self, Erc20, IErc20};
use stylus_sdk::{
    alloy_primitives::{Address, U256},
    prelude::*,
};

#[entrypoint]
#[storage]
struct Erc20Example {
    erc20: Erc20,
}

#[public]
#[implements(IErc20<Error = erc20::Error>)]
impl Erc20Example {}

#[public]
impl IErc20 for Erc20Example {
    type Error = erc20::Error;

    fn total_supply(&self) -> U256 {
        self.erc20.total_supply()
    }

    fn balance_of(&self, account: Address) -> U256 {
        self.erc20.balance_of(account)
    }

    fn transfer(
        &mut self,
        to: Address,
        value: U256,
    ) -> Result<bool, Self::Error> {
        self.erc20.transfer(to, value)
    }

    fn allowance(&self, owner: Address, spender: Address) -> U256 {
        self.erc20.allowance(owner, spender)
    }

    fn approve(
        &mut self,
        spender: Address,
        value: U256,
    ) -> Result<bool, Self::Error> {
        self.erc20.approve(spender, value)
    }

    fn transfer_from(
        &mut self,
        from: Address,
        to: Address,
        value: U256,
    ) -> Result<bool, Self::Error> {
        self.erc20.transfer_from(from, to, value)
    }
}

For a working demo with deployment and queries, check out the basic example.

📚 Resources

• Examples: Browse our examples folder for full project templates.
• Test helpers: See unit and integration testing utilities.
• Roadmap: Follow planned features and modules in our roadmap.

🤝 Contribute

OpenZeppelin Contracts for Stylus exists thanks to its contributors. There are many ways you can participate and help build high-quality software. Check out the contribution guide!

🔐 Security

• Past audits: See the audits folder.
• Refer to our Security Policy for guidelines on reporting vulnerabilities.

⚖️ License

OpenZeppelin Contracts for Stylus is released under the MIT License.