openzeppelin-contracts/contracts/token/ERC721/README.adoc

= ERC-721

[.readme-notice]
NOTE: This document is better viewed at https://docs.openzeppelin.com/contracts/api/token/erc721

This set of interfaces, contracts, and utilities are all related to the https://eips.ethereum.org/EIPS/eip-721[ERC-721 Non-Fungible Token Standard].

TIP: For a walk through on how to create an ERC-721 token read our xref:ROOT:erc721.adoc[ERC-721 guide].

The ERC specifies four interfaces:

* {IERC721}: Core functionality required in all compliant implementation.
* {IERC721Metadata}: Optional extension that adds name, symbol, and token URI, almost always included.
* {IERC721Enumerable}: Optional extension that allows enumerating the tokens on chain, often not included since it requires large gas overhead.
* {IERC721Receiver}: An interface that must be implemented by contracts if they want to accept tokens through `safeTransferFrom`.

OpenZeppelin Contracts provides implementations of all four interfaces:

* {ERC721}: The core and metadata extensions, with a base URI mechanism.
* {ERC721Enumerable}: The enumerable extension.
* {ERC721Holder}: A bare bones implementation of the receiver interface.

Additionally there are a few of other extensions:

* {ERC721Consecutive}: An implementation of https://eips.ethereum.org/EIPS/eip-2309[ERC-2309] for minting batches of tokens during construction, in accordance with ERC-721.
* {ERC721URIStorage}: A more flexible but more expensive way of storing metadata.
* {ERC721Votes}: Support for voting and vote delegation.
* {ERC721Royalty}: A way to signal royalty information following ERC-2981.
* {ERC721Pausable}: A primitive to pause contract operation.
* {ERC721Burnable}: A way for token holders to burn their own tokens.
* {ERC721Wrapper}: Wrapper to create an ERC-721 backed by another ERC-721, with deposit and withdraw methods. Useful in conjunction with {ERC721Votes}.

NOTE: This core set of contracts is designed to be unopinionated, allowing developers to access the internal functions in ERC-721 (such as <<ERC721-_mint-address-uint256-,`_mint`>>) and expose them as external functions in the way they prefer.

== Core

{{IERC721}}

{{IERC721Metadata}}

{{IERC721Enumerable}}

{{ERC721}}

{{ERC721Enumerable}}

{{IERC721Receiver}}

== Extensions

{{ERC721Pausable}}

{{ERC721Burnable}}

{{ERC721Consecutive}}

{{ERC721URIStorage}}

{{ERC721Votes}}

{{ERC721Royalty}}

{{ERC721Wrapper}}

== Utilities

{{ERC721Holder}}

{{ERC721Utils}}