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README.md

Foundry ERC-721 NFT

What is an NFT

ERC-721 NON-FUNGIBLE TOKEN STANDARD

EIP-721

OpenZeppelin - ERC-721 Docs

OpenZeppelin - ERC-721 Contract

What is a Non-Fungible Token?

A Non-Fungible Token (NFT) is used to identify something or someone in a unique way. This type of Token is perfect to be used on platforms that offer collectible items, access keys, lottery tickets, numbered seats for concerts and sports matches, etc. This special type of Token has amazing possibilities so it deserves a proper Standard, the ERC-721 came to solve that!

What is ERC-721?

The ERC-721 introduces a standard for NFT, in other words, this type of Token is unique and can have different value than another Token from the same Smart Contract, maybe due to its age, rarity or even something else like its visual.

All NFTs have a uint256 variable called tokenId, so for any ERC-721 Contract, the pair contract address, uint256 tokenId must be globally unique.

Prerequisites

  • Accounts
  • Smart Contracts
  • Token standards

If a Smart Contract implements the following methods and events it can be called an ERC-721 Non-Fungible Token Contract:

Methods

    function balanceOf(address _owner) external view returns (uint256);
    function ownerOf(uint256 _tokenId) external view returns (address);
    function safeTransferFrom(address _from, address _to, uint256 _tokenId, bytes data) external payable;
    function safeTransferFrom(address _from, address _to, uint256 _tokenId) external payable;
    function transferFrom(address _from, address _to, uint256 _tokenId) external payable;
    function approve(address _approved, uint256 _tokenId) external payable;
    function setApprovalForAll(address _operator, bool _approved) external;
    function getApproved(uint256 _tokenId) external view returns (address);
    function isApprovedForAll(address _owner, address _operator) external view returns (bool);

Events

    event Transfer(address indexed _from, address indexed _to, uint256 indexed _tokenId);
    event Approval(address indexed _owner, address indexed _approved, uint256 indexed _tokenId);
    event ApprovalForAll(address indexed _owner, address indexed _operator, bool _approved);

IPFS

IPFS

What is IPFS

EVM Overview

Transaction

Verifying a transaction in Metamask

  1. Check the address (read the function)
  2. Check the function selector
  3. Decode the calldata (check the parameters)

Fire

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