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OpenZeppelin Contracts is a library for secure smart contract development.
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dependabot-preview and nventuro [Security] Bump eslint-utils from 1.4.0 to 1.4.3 (#2064)
Bumps [eslint-utils]( from 1.4.0 to 1.4.3. **This update includes security fixes.**
- [Release notes](
- [Commits](mysticatea/eslint-utils@v1.4.0...v1.4.3)

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Latest commit 5a67a69 Jan 27, 2020
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.circleci Migrate from truffle to test-environment (#2007) Nov 28, 2019
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audit Add latest audit to repository (#1664) Mar 1, 2019
contracts Reorder functions to prevent shadowing warning Jan 24, 2020
docs Implementation of an address Enumerable Set (#2061) Jan 24, 2020
migrations Clean up npm package (#904) Apr 26, 2018
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.eslintrc Migrate from truffle to test-environment (#2007) Nov 28, 2019
.gitattributes feat: add solidity syntax highlighting directive, fixes #671 Jan 15, 2018
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package-lock.json [Security] Bump eslint-utils from 1.4.0 to 1.4.3 (#2064) Jan 27, 2020
package.json Bump mocha from 7.0.0 to 7.0.1 (#2066) Jan 27, 2020
test-environment.config.js Migrate from truffle to test-environment (#2007) Nov 28, 2019


NPM Package Build Status Coverage Status

A library for secure smart contract development. Build on a solid foundation of community-vetted code.



$ npm install @openzeppelin/contracts

OpenZeppelin 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 ^0.5.0;

import "@openzeppelin/contracts/token/ERC721/ERC721Full.sol";
import "@openzeppelin/contracts/token/ERC721/ERC721Mintable.sol";

contract MyNFT is ERC721Full, ERC721Mintable {
    constructor() ERC721Full("MyNFT", "MNFT") public {

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.

Learn More

The guides in the sidebar will teach about different concepts, and how to use the related contracts that OpenZeppelin Contracts provides:

  • Access Control: decide who can perform each of the actions on your system.
  • Tokens: create tradeable assets or collectives, and distribute them via Crowdsales.
  • Gas Station Network: let your users interact with your contracts without having to pay for gas themselves.
  • Utilities: generic useful tools, including non-overflowing math, signature verification, and trustless paying systems.

The full API is also thoroughly documented, and serves as a great reference when developing your smart contract application. You can also ask for help or follow Contracts's development in the community forum.

Finally, you may want to take a look at the guides on our blog, which cover several common use cases and good practices.. The following articles provide great background reading, though please note, some of the referenced tools have changed as the tooling in the ecosystem continues to rapidly evolve.


This project is maintained by OpenZeppelin, and developed following our high standards for code quality and security. OpenZeppelin 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 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


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


OpenZeppelin is released under the MIT License.

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