OpenZeppelin Contracts for Cairo

A library for secure smart contract development written in Cairo for Starknet, a decentralized ZK Rollup.

Warning This repo contains highly experimental code. It has no code coverage checks. It hasn't been audited. Use at your own risk.

Usage

Warning Expect rapid iteration. Some contracts or features are not ready to be deployed. Check the Unsupported section below.

Prepare the environment

Simply install Cairo and scarb.

Set up your project

Create a new project and cd into it.

scarb new my_project && cd my_project

The contents of my_project should look like this:

$ ls

Scarb.toml src

Install the library

Edit scarb.toml and add:

[dependencies]
openzeppelin = { git = "https://github.com/OpenZeppelin/cairo-contracts.git", tag = "v0.16.0" }

The previous example would import the entire library. we can also add each package as a separated dependency to improve the time for building by not including modules that won't be used:

[dependencies]
openzeppelin_token = { git = "https://github.com/OpenZeppelin/cairo-contracts.git", tag = "v0.16.0" }

Build the project to download it:

$ scarb build

Updating git repository https://github.com/OpenZeppelin/cairo-contracts
Compiling my_project v0.1.0 (~/my_project/Scarb.toml)
Finished release target(s) in 6 seconds

Using the library

Open src/lib.cairo and write your contract.

For example, this is how to write an ERC20-compliant contract:

#[starknet::contract]
mod MyToken {
    // If only the token package was added as a dependency, use `openzeppelin_token::` instead
    use openzeppelin::token::erc20::{ERC20Component, ERC20HooksEmptyImpl};
    use starknet::ContractAddress;

    component!(path: ERC20Component, storage: erc20, event: ERC20Event);

    // ERC20 Mixin
    #[abi(embed_v0)]
    impl ERC20MixinImpl = ERC20Component::ERC20MixinImpl<ContractState>;
    impl ERC20InternalImpl = ERC20Component::InternalImpl<ContractState>;

    #[storage]
    struct Storage {
        #[substorage(v0)]
        erc20: ERC20Component::Storage
    }

    #[event]
    #[derive(Drop, starknet::Event)]
    enum Event {
        #[flat]
        ERC20Event: ERC20Component::Event
    }

    #[constructor]
    fn constructor(
        ref self: ContractState,
        initial_supply: u256,
        recipient: ContractAddress
    ) {
        let name = "MyToken";
        let symbol = "MTK";

        self.erc20.initializer(name, symbol);
        self.erc20.mint(recipient, initial_supply);
    }
}

Unsupported

DualCase dispatchers rely on Sierra's ability to catch a revert to resume execution. Currently, Starknet live chains (testnets and mainnet) don't implement that behavior. Starknet's testing framework does support it.

Learn

Cairo

Tooling

Scarb

Development

Note: You can track our roadmap and future milestones in our Github Project.

OpenZeppelin Contracts for Cairo exists thanks to its contributors. There are many ways you can participate and help build high quality software, make sure to check out the contribution guide in advance.

Set up the project

Clone the repository:

git clone git@github.com:OpenZeppelin/cairo-contracts.git

cd into it and build:

cd cairo-contracts
scarb build -w

Run tests

snforge test -w

Security

⚠️ 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.

Refer to SECURITY.md for more details.

License

OpenZeppelin Contracts for Cairo is released under the MIT License.

Readme