A library for secure smart contract development. Build on a solid foundation of community-vetted code.
- Implementations of standards like ERC20 and ERC721.
- Flexible role-based permissioning scheme.
- Reusable Solidity components to build custom contracts and complex decentralized systems.
🧙 Not sure how to get started? Check out Contracts Wizard — an interactive smart contract generator.
$ npm install @openzeppelin/contractsOpenZeppelin Contracts features a stable API, which means your contracts won't break unexpectedly when upgrading to a newer minor version.
Once installed, you can use the contracts in the library by importing them:
pragma solidity ^0.8.0;
import "@openzeppelin/contracts/token/ERC721/ERC721.sol";
contract MyCollectible is ERC721 {
constructor() ERC721("MyCollectible", "MCO") {
}
}If you're new to smart contract development, head to Developing Smart Contracts to learn about creating a new project and compiling your contracts.
To keep your system secure, you should always use the installed code as-is, and neither copy-paste it from online sources, nor modify it yourself. The library is designed so that only the contracts and functions you use are deployed, so you don't need to worry about it needlessly increasing gas costs.
This project is maintained by OpenZeppelin, and developed following our high standards for code quality and security. OpenZeppelin Contracts is meant to provide tested and community-audited code, but please use common sense when doing anything that deals with real money! We take no responsibility for your implementation decisions and any security problems you might experience.
The core development principles and strategies that OpenZeppelin Contracts is based on include: security in depth, simple and modular code, clarity-driven naming conventions, comprehensive unit testing, pre-and-post-condition sanity checks, code consistency, and regular audits.
The latest audit was done on October 2018 on version 2.0.0.
Please report any security issues you find to security@openzeppelin.org.