OpenZeppelin Contracts

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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.

:mage: Not sure how to get started? Check out Contracts Wizard — an interactive smart contract generator.

> [!IMPORTANT]
> OpenZeppelin Contracts uses semantic versioning to communicate backwards compatibility of its API and storage layout. For upgradeable contracts, the storage layout of different major versions should be assumed incompatible, for example, it is unsafe to upgrade from 4.9.3 to 5.0.0. Learn more at Backwards Compatibility.

Overview

Release tags

We use NPM tags to clearly distinguish between audited and non-audited versions of our package:

| Tag | Purpose | Description |
| :--------- | :----------------------- | :---------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| latest | ✅ Audited releases | Stable, audited versions of the package. This is the default version installed when users run npm install @openzeppelin/contracts. |
| dev | 🧪 Final but not audited | Versions that are finalized and feature-complete but have not yet been audited. This version is fully tested, can be used in production and is covered by the bug bounty. |
| next | 🚧 Release

... [truncated — view full README on GitHub]