The NFT boom in 2020 attracted millions to the Web3 space. Its sundry use cases allowed users to experiment, give a voice to their art, earn a steady income, etc. As a result, NFTs today have become an integral part of Web3 startups. This course teaches you to create NFTs using different token standards, understand the difference between them along with what opportunities lie in the NFT zone for you.

Learn the art of minting NFTs on any token standard to up your NFT game and enhance your minting skills. Enroll now.

Create NFTs Using Different Token Standards

Introduction to the world of NFTs and what we will be covering in this mini project based opportunity.

<p>Mirror mirror on the wall, NFT is the best investment of them all! 😱 Just kidding! 😂</p><p>Ever wondered why NFTs have become so popular and dominant in such a short span of time that their adoption rate has almost topped the adoption curve of new technologies? Well, the reason is quite simple. The technology provides a whole spectrum of opportunities to verify the genuineness and authenticty of a non-fungible asset. It has given rise to a safe and sound business viewpoint around non-fungible assets. All thanks to the amazing blockchain technology behind it that the acceptance and adoption rate speaks for its verity itself.</p><p>Does this excite you enough to deep dive into how this amazing technology is internally pulled off? If yes, then you're exactly at the right spot and won't regret spending your time here.</p><p>Hey fam, I am <a href="https://www.linkedin.com/in/ismailvohra/" target="_blank" rel="noopener noreferrer">Ismail Vohra</a> and today we will be discussing the different token standards available for creating NFTs on the Ethereum Blockchain. To be precise, our focus will be on ERC-721, ERC-721A and ERC-1155.</p><p>Within the scope of this tutorial, you will enlighten your knowledge about:</p><ol><li>The basics about ERC-721, ERC-721A and ERC-1155</li><li>How to write a basic smart contract using ERC-721, ERC-721A and ERC-1155</li><li>Use Cases and Applications for the respective token standard</li><li>Comparison of the token standards</li></ol><p>Now before we move forward, let's set some house rules first:</p><ol><li>Pleaseeeee do your quick assignments properly.</li><li>Join our discord server and ask all relevant questions there.</li><li>Stay happy and positive!</li></ol><p>Let's begin together this journey of NFT exploration!</p><p></p><figure class="image"><div class="se-component se-image-container __se__float-none" contenteditable="false"><figure class="image" style="margin: 0px;"><img src="https://metaschool.s3-ap-southeast-1.amazonaws.com/images/ZCueNhZ1fwQDdWx0KYjKjwxShaOTRBSPqHLSwz1I.gif" data-origin="," alt="" data-proportion="true" data-align="none" data-file-name="ZCueNhZ1fwQDdWx0KYjKjwxShaOTRBSPqHLSwz1I.gif" data-file-size="0" data-rotate="" data-rotatex="" data-rotatey="" data-size="," data-percentage="auto,auto" style="" data-index="0"></figure></div></figure><figure class="image"><div class="se-component se-image-container __se__float-none" contenteditable="false"><figure class="image" style="margin: 0px;"><img data-origin="," alt="" data-proportion="true" data-align="none" data-file-name="" data-file-size="0" data-rotate="" data-rotatex="" data-rotatey="" data-size="," data-percentage="auto,auto" style="" data-index="1"></figure></div></figure><p></p>

# What Are We Building Today?

gm everyone 🌈, I am very excited to bring the exciting course for developers just like you, who want to get started with the NFTs ecosystem!

So what are we building today? Today I will be helping you create NFTs on the Ethereum Blockchain using d token standards. To be precise, my focus will be on building NFTs using ERC-721, ERC-721A and ERC-1155 token standards.

Why NFTs? The technology provides a whole spectrum of opportunities to verify the genuineness and authenticity of a digital asset. It has given rise to a safe and sound business viewpoint around non-fungible assets. All thanks to the amazing blockchain technology behind it that the acceptance and adoption rate speaks for its verity itself.

Not only this, you can also earn money using NFTs. Around 5K NFTs are being sold daily as of April 2023. "The Merge" is the biggest authentic NFT sale to date that was sold for $91.8 million in December 2021.

## Course overview

Within the scope of this tutorial, you will enlighten your knowledge about:

1.  The basics about ERC-721, ERC-721A and ERC-1155
2.  How to write a basic smart contract using ERC-721, ERC-721A and ERC-1155
3.  Use Cases and Applications for the respective token standard
4.  Comparison of the token standards

## Who exactly should take this course?

This course is for beginners web3 developers who wish to learn about different NFTs token standards in the Ethereum Blockchain.

## Prerequisites

Learning about token standards on Ethereum Blockchain will be much easier if you are familiar with:

1. Ethereum Blockchain
2. NFTs

Since in this course, I will be diving straight into the different token standards present in Ethereum Blockchain, your familarity with Ethereum Blockchain and NFTs itself is necessary.

> **Note:** If you don't have prior knowledge of NFTs, please feel free to explore our course, [Learn everything about NFTs](https://metaschool.so/courses/learn-everything-about-nfts), first. After completing that course, you can come back to this one.

## Proof of completion

If you complete this course with me today, you will be getting a special NFT, a utility token, which will unlock many more opportunities for you on the Metaschool platform. Here is how the NFT looks like.

![Untitled (1)](https://github.com/0xmetaschool/Learning-Projects/blob/main/assests_for_all/course%20NFT.gif?raw=true)

Now before we move forward, let’s set some house rules first.
1. Pleaseeeee do your quick assignments properly.
2. Join [our discord server](https://discord.gg/vbVMUwXWgc) and ask all relevant questions there.
3. We are a free open-source platform and if you follow us on [X](https://bit.ly/token-stnd-twitter) and [LinkedIn](https://bit.ly/token-stnd-linkedin), it would be a great support. 🫣
4. Stay happy and positive!




Alright guys, no need to wait any longer, let's start our NFTs exploration! 🙌


https://raw.githubusercontent.com/0xmetaschool/Learning-Projects/main/Creating%20NFTs%20using%20different%20token%20standards/1.%20Let's%20Get%20Started/1.%20What%20Are%20We%20Building%20Today%3F.md

What Are We Building Today?

Darya

Kenny

Just call me Olaf

Introduction

<p>In January 2018, William Entriken, Dieter Shirley, Jacob Evans, and Nastassia Sachs presented the ERC-721 (Ethereum Request for Comments 721) standard (aka the golden standard), which is considered the evergreen Non-fungible Token standard that specifies an API for non-fungible tokens within smart contracts.</p><p>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. Wait, visual?</p><p>Yes! All NFTs have a <code>uint256</code> variable called <code>tokenId</code>, so for any ERC-721 contract, the pair contract address, <code>uint256</code> <code>tokenId</code> must be globally unique. That said, a dApp can have a "converter" that uses the <code>tokenId</code> as input and outputs an image of something cool, like zombies, weapons, skills or amazing kitties!</p><p></p><figure class="image"><div class="se-component se-image-container __se__float-none" contenteditable="false"><figure class="image" style="margin: 0px;"><img src="https://metaschool.s3-ap-southeast-1.amazonaws.com/images/ZKTYieX72kIS2Ry6Gt5926YQMHbInAGakEtzYkMu.gif" data-origin="," alt="" data-proportion="true" data-align="none" data-file-name="ZKTYieX72kIS2Ry6Gt5926YQMHbInAGakEtzYkMu.gif" data-file-size="0" data-rotate="" data-rotatex="" data-rotatey="" data-size="," data-percentage="auto,auto" style="" data-index="0"></figure></div></figure><p></p><p>Starting to get impressed with ERC-721 already? Hehe, hang on there's more.</p><h2><strong>Definition of ERC-721 Smart Contract</strong></h2><p>Now that we have briefly discussed the contract itself, let's look at how it can be created.</p><p>Creating a smart contract that is ERC-721 compliant is fairly easy and is quite rewarding too. If a smart contract implements the following methods, it can be deemed as an ERC-721 (NFT) contract.</p><pre><code>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);</code></pre><p>A fairly straight-forward interface, right? Now let's get to writing your contract.</p>

# ERC-721 – The Golden Standard

In January 2018, William Entriken, Dieter Shirley, Jacob Evans, and Nastassia Sachs presented the ERC-721 (Ethereum Request for Comments 721) standard (aka the golden standard), which is considered the evergreen Non-fungible Token standard that specifies an API for non-fungible tokens within smart contracts.

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. Wait, visual?

Yes! All NFTs have a `uint256` variable called `tokenId`, so for any ERC-721 contract, the pair contract address, `uint256` `tokenId` must be globally unique. That said, a dApp can have a "converter" that uses the `tokenId` as input and outputs an image of something cool, like zombies, weapons, skills or amazing kitties!

![](https://metaschool.s3-ap-southeast-1.amazonaws.com/images/ZKTYieX72kIS2Ry6Gt5926YQMHbInAGakEtzYkMu.gif)

Starting to get impressed with ERC-721 already? Hehe, hang on there's more.

## Definition of ERC-721 Smart Contract

Now that we have briefly discussed the contract itself, let's look at how it can be created.

Creating a smart contract that is ERC-721 compliant is fairly easy and is quite rewarding too. If a smart contract implements the following methods, it can be deemed as an ERC-721 (NFT) contract.

```reasonml
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);

```

A fairly straight-forward interface, right? Now let's get to writing your contract.


https://raw.githubusercontent.com/0xmetaschool/Learning-Projects/main/Creating%20NFTs%20using%20different%20token%20standards/2.%20ERC721/1.%20ERC-721%20%E2%80%93%20The%20Golden%20Standard.md

ERC-721 – The Golden Standard

<p>If you're creating a smart contract then you obviously would want to make sure that it is surrounded by an ecosystem that takes complete precautionary security measures into account for your contracts. <a href="https://openzeppelin.com/" target="_blank" rel="noopener noreferrer">OpenZeppelin</a> exactly helps with that!</p><p>In this section, we'll try and figure out how to create an ERC-721 contract with OpenZeppelin.</p><p>Creating an ERC-721 Contract with Open Zeppelin is relatively simple. For development purposes, we will use <a href="https://remix.ethereum.org/" target="_blank" rel="noopener noreferrer">Remix</a> as our IDE for writing, compiling, and deploying the contract. If you wish to jump directly to the complete smart contract, here is a copy of it.</p><pre><code>// SPDX-License-Identifier:UNLICENSEDpragma solidity ^0.8.9;import "@openzeppelin/contracts/token/ERC721/ERC721.sol";contract Hellonft is ERC721("HelloNft", "HNFT") {    uint tokenId;    mapping(address=&gt;tokenMetaData[]) public ownershipRecord;    struct tokenMetaData {        uint tokenId;        uint timeStamp;        string tokenURI;    }    function mintToken(address recipient, string memory url) public {        _safeMint(recipient, tokenId);        ownershipRecord[recipient].push(tokenMetaData(tokenId, block.timestamp, url));        tokenId = tokenId + 1;    }}</code></pre><p></p><figure class="image"><div class="se-component se-image-container __se__float-none" contenteditable="false"><figure class="image" style="margin: 0px;"><img src="https://metaschool.s3-ap-southeast-1.amazonaws.com/images/3cf2NqkqArRzSpzo93n7WsRGMv9FXD03rV2yitDE.gif" data-origin="," alt="" data-proportion="true" data-align="none" data-file-name="3cf2NqkqArRzSpzo93n7WsRGMv9FXD03rV2yitDE.gif" data-file-size="0" data-rotate="" data-rotatex="" data-rotatey="" data-size="," data-percentage="auto,auto" style="" data-index="0"></figure></div></figure><p></p><p>Don't get too overwhelmed by looking at the entire contract upfront. This was just a quick snapshot. More details follow 😄</p><p>Let's get started with the step-by-step overview of this contract.</p><h2><strong>Headers of the Contract</strong></h2><p>We will define the Solidity compiler version using pragma. We will also import the respective Open Zeppelin library from their official repo, namely, <em>Ownable</em> <em>ERC721</em>. The ERC721 library includes the basic definitions for a contract to be rightfully ERC-721 standard:</p><pre><code>pragma solidity ^0.8.9;import “https://github.com/OpenZeppelin/openzeppelin-contracts/contracts/token/ERC721/ERC721.sol";</code></pre><h2><strong>Body of the Contract</strong></h2><p>We will name our contract <em>Hellonft</em> and inherit the Open Zeppelin library <em>ERC721</em> into our contract</p><pre><code>contract Hellonft is ERC721(){}</code></pre><p>We will now define the name and symbol of our contract in the ERC721 constructor as <em>HelloNft</em> and <em>HFNT</em>, respectively</p><pre><code>contract Hellonft is Ownable, ERC721(“HelloNft”, “HNFT”){}</code></pre><p>The tokenId (unique identifier for each token) is initialized (to 0)</p><pre><code>uint tokenId;</code></pre><p>A mapping is initialized with <em>key</em> as <em>address</em> and <em>value</em> as <em>tokenMetaData</em></p><pre><code>mapping(address=&gt;tokenMetaData[]) public ownershipRecord;</code></pre><p>The tokenMetaData struct is defined to keep tokenId, timestamp and tokenURI of each token in one place, so as to be connected to the ownershipRecord of addresses in a comprehensive way.</p><pre><code>struct tokenMetaData{    uint tokenId;    uint timeStamp;    string tokenURI;}</code></pre><p>We will now write our <em>mintToken</em> function. Minting in an NFT is the process of tokenizing an asset. In our case, we will mint a sample image and use its <em>URL</em> as <em>tokenURI</em>.</p><p>Let's define our <em>mint</em> function as <em>mintToken</em>. We pass in the <em>address</em> of the <em>receiver</em> (to whom to mint to) and the <em>url</em> of the <em>asset</em> (to <em>mint</em>) as parameters to our function:</p><pre><code>function mintToken(address recipient, string memory url) public {}</code></pre><p>We now start the minting process imported from the ERC721 contract using the _safeMint function and maintain our own ownershipRecords by pushing the <em>tokenMetaData</em> to the recipient.</p><pre><code>_safeMint(receiver, tokenId);ownershipRecord[recipient].push(tokenMetaData(tokenId, block.timestamp, url));tokenId = tokenId + 1;</code></pre><p>You may now proceed to deploy the contract on the Remix VMs or any other testnets and play around.</p><p>You might notice a plethora of available mutational and querying functions available from inherited contracts. For now, they are beyond the scope of this article but we will definitely deep dive more into them in our upcoming tutorials.</p><p>Call in the <em>mintToken</em> function, pass in the <em>address</em> (of the <em>receiver</em>) and <em>url</em> (of the <em>asset</em>), and you will have tokenized your very first NFT.</p><p>PS. You may use the following image <em>url</em> from Pexels for testing purposes: <a href="https://images.pexels.com/photos/1097946/pexels-photo-1097946.jpeg" target="_blank" rel="noopener noreferrer">https://images.pexels.com/photos/1097946/pexels-photo-1097946.jpeg</a></p><p>You did it! You finally did it! You should be proud of making it this far.</p>

# Creating an ERC-721 Contract with Open Zeppelin

If you're creating a smart contract then you obviously would want to make sure that it is surrounded by an ecosystem that takes complete precautionary security measures into account for your contracts. [OpenZeppelin](https://openzeppelin.com/) exactly helps with that!

In this section, we'll try and figure out how to create an ERC-721 contract with OpenZeppelin.

Creating an ERC-721 Contract with Open Zeppelin is relatively simple. For development purposes, we will use [Remix](https://remix.ethereum.org/) as our IDE for writing, compiling, and deploying the contract. If you wish to jump directly to the complete smart contract, here is a copy of it.

```reasonml
// SPDX-License-Identifier:UNLICENSED

pragma solidity ^0.8.9;

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

contract Hellonft is ERC721("HelloNft", "HNFT") {
    uint tokenId;
    mapping(address=>tokenMetaData[]) public ownershipRecord;

    struct tokenMetaData {
        uint tokenId;
        uint timeStamp;
        string tokenURI;
    }

    function mintToken(address recipient, string memory url) public {
        _safeMint(recipient, tokenId);
        ownershipRecord[recipient].push(tokenMetaData(tokenId, block.timestamp, url));
        tokenId = tokenId + 1;
    }
}
```

![](https://metaschool.s3-ap-southeast-1.amazonaws.com/images/3cf2NqkqArRzSpzo93n7WsRGMv9FXD03rV2yitDE.gif)

Don't get too overwhelmed by looking at the entire contract upfront. This was just a quick snapshot. More details follow 😄

Let's get started with the step-by-step overview of this contract.

## Headers of the Contract

We will define the Solidity compiler version using pragma. We will also import the respective Open Zeppelin library from their official repo, namely, _Ownable_ _ERC721_. The ERC721 library includes the basic definitions for a contract to be rightfully ERC-721 standard:

```awk
pragma solidity ^0.8.9;

import “https://github.com/OpenZeppelin/openzeppelin-contracts/contracts/token/ERC721/ERC721.sol";
```

## Body of the Contract

We will name our contract _Hellonft_ and inherit the Open Zeppelin library _ERC721_ into our contract

```csharp
contract Hellonft is ERC721(){}
```

We will now define the name and symbol of our contract in the ERC721 constructor as _HelloNft_ and _HFNT_, respectively

```wren
contract Hellonft is Ownable, ERC721(“HelloNft”, “HNFT”){}
```

The tokenId (unique identifier for each token) is initialized (to 0)

```abnf
uint tokenId;
```

A mapping is initialized with _key_ as _address_ and _value_ as _tokenMetaData_

```abnf
mapping(address=>tokenMetaData[]) public ownershipRecord;
```

The tokenMetaData struct is defined to keep tokenId, timestamp and tokenURI of each token in one place, so as to be connected to the ownershipRecord of addresses in a comprehensive way.

```csharp
struct tokenMetaData{
    uint tokenId;
    uint timeStamp;
    string tokenURI;
}
```

We will now write our _mintToken_ function. Minting in an NFT is the process of tokenizing an asset. In our case, we will mint a sample image and use its _URL_ as _tokenURI_.

Let's define our _mint_ function as _mintToken_. We pass in the _address_ of the _receiver_ (to whom to mint to) and the _url_ of the _asset_ (to _mint_) as parameters to our function:

```reasonml
function mintToken(address recipient, string memory url) public {}
```

We now start the minting process imported from the ERC721 contract using the _safeMint function and maintain our own ownershipRecords by pushing the \_tokenMetaData_ to the recipient.

```reasonml
_safeMint(receiver, tokenId);
ownershipRecord[recipient].push(tokenMetaData(tokenId, block.timestamp, url));
tokenId = tokenId + 1;
```

You may now proceed to deploy the contract on the Remix VMs or any other testnets and play around.

You might notice a plethora of available mutational and querying functions available from inherited contracts. For now, they are beyond the scope of this article but we will definitely deep dive more into them in our upcoming tutorials.

Call in the _mintToken_ function, pass in the _address_ (of the _receiver_) and _url_ (of the _asset_), and you will have tokenized your very first NFT.

PS. You may use the following image _url_ from Pexels for testing purposes: [https://images.pexels.com/photos/1097946/pexels-photo-1097946.jpeg](https://images.pexels.com/photos/1097946/pexels-photo-1097946.jpeg)

You did it! You finally did it! You should be proud of making it this far.


https://raw.githubusercontent.com/0xmetaschool/Learning-Projects/main/Creating%20NFTs%20using%20different%20token%20standards/2.%20ERC721/2.%20Creating%20an%20ERC-721%20Contract%20with%20Open%20Zeppelin.md

Creating an ERC-721 Contract with Open Zeppelin

<p>In their individual smart contracts, all coins based on the ERC-721 standard save information. The ERC-721 differs from previous standards in that it indicates the ownership of non-divisible assets or asset tokenization. It is based on a single unique asset that is not interchangeable. ERC-721 provides a major improvement in transparency, security, and immutability in terms of ownership. This standard has long been the face of NFTs, including several that have gotten a lot of coverage. Among the most popular are Cryptokitties and Bored Ape Yacht Club.</p><h3><strong>Cryptokitties</strong></h3><p><a href="https://www.cryptokitties.co/" target="_blank" rel="noopener noreferrer">Cryptokitties</a> is a popular game centered around breedable and collectible adorable creatures called cryptokitties. Each of these cats is one of its kind and unique which no other individual possesses, it cannot be replicated, taken away, or destroyed.</p><h3><strong>Bored Ape Yacht Club(BAYC)</strong></h3><p><a href="https://boredapeyachtclub.com/" target="_blank" rel="noopener noreferrer">BAYC</a> is a collection of over 10,000 unique NFTs that are rare one-of-a-kind art, and it is another classic example of an ERC-721-based token. These pieces also serve as a membership token for the club, as well as offering rewards that rise over time as a result of the community's efforts.</p><h2><strong>Enticing Yet Full of Caveats</strong></h2><p>The ERC-721 does seem like the dream standard doesn't it? If you think so you might want to re-evaluate your decision after we have told you about obvious caveats in its system and mode of operation.</p><h3><strong>The Nightmare of Bulk Transfer</strong></h3><p>Despite the roaring popularity of the ERC-721 standard, it comes with some obvious and serious disadvantages, one of which is the great difficulty while making bulk transfers. The cryptokitties craze suddenly came to a befitting end when investors truly discovered the limitations of the Ethereum network. The problem with ERC-721 is that it only permits transferring tokens one by one which means if you want to transfer 30 tokens, for example, to the same person, you will need to send 30 individual transactions. These transactions are not cheap and a single one takes up a significant amount of gas which increases the overall cost and burden on the network. As a result of all this, the network’s load operations get compromised which reduces the usability of the network. You might want to consider other standards if you plan to regularly make bulk transfers.</p><h3><strong>Inability to Get Token Ids</strong></h3><p>If you refer back to our <em>Definition of ERC-721 Smart Contract</em> section, you will notice that there is no functionality to get your token ids from the contract. This limitation may not sound like a caveat right now but remember that the only way to make a transfer in ERC721 is to reference your token id. A possible workaround would be to loop through <em>token id</em> which is not only an expensive operation but also a time-consuming one. For scalable and popular contracts, this could mean a lot of wait and cost to the user in consuming your contract.</p><h3><strong>Test Your Knowledge</strong></h3><p>ERC-721 token standard only support?<br>(a). Fungible Tokens<br>(b). Non-Fungible Tokens<br>(c). Semi-Fungible Tokens<br>(d). None of the Above</p>

# ERC-721 Use Cases

In their individual smart contracts, all coins based on the ERC-721 standard save information. The ERC-721 differs from previous standards in that it indicates the ownership of non-divisible assets or asset tokenization. It is based on a single unique asset that is not interchangeable. ERC-721 provides a major improvement in transparency, security, and immutability in terms of ownership. This standard has long been the face of NFTs, including several that have gotten a lot of coverage. Among the most popular are Cryptokitties and Bored Ape Yacht Club.

## Cryptokitties

[Cryptokitties](https://www.cryptokitties.co/) is a popular game centered around breedable and collectible adorable creatures called cryptokitties. Each of these cats is one of its kind and unique which no other individual possesses, it cannot be replicated, taken away, or destroyed.

## Bored Ape Yacht Club(BAYC)

[BAYC](https://boredapeyachtclub.com/) is a collection of over 10,000 unique NFTs that are rare one-of-a-kind art, and it is another classic example of an ERC-721-based token. These pieces also serve as a membership token for the club, as well as offering rewards that rise over time as a result of the community's efforts.

## Enticing Yet Full of Caveats

The ERC-721 does seem like the dream standard doesn't it? If you think so you might want to re-evaluate your decision after we have told you about obvious caveats in its system and mode of operation.

## The Nightmare of Bulk Transfer

Despite the roaring popularity of the ERC-721 standard, it comes with some obvious and serious disadvantages, one of which is the great difficulty while making bulk transfers. The cryptokitties craze suddenly came to a befitting end when investors truly discovered the limitations of the Ethereum network. The problem with ERC-721 is that it only permits transferring tokens one by one which means if you want to transfer 30 tokens, for example, to the same person, you will need to send 30 individual transactions. These transactions are not cheap and a single one takes up a significant amount of gas which increases the overall cost and burden on the network. As a result of all this, the network’s load operations get compromised which reduces the usability of the network. You might want to consider other standards if you plan to regularly make bulk transfers.

## Inability to Get Token Ids

If you refer back to our _Definition of ERC-721 Smart Contract_ section, you will notice that there is no functionality to get your token ids from the contract. This limitation may not sound like a caveat right now but remember that the only way to make a transfer in ERC721 is to reference your token id. A possible workaround would be to loop through _token id_ which is not only an expensive operation but also a time-consuming one. For scalable and popular contracts, this could mean a lot of wait and cost to the user in consuming your contract.


https://raw.githubusercontent.com/0xmetaschool/Learning-Projects/main/Creating%20NFTs%20using%20different%20token%20standards/2.%20ERC721/3.%20ERC-721%20Use%20Cases.md

ERC-721 Use Cases

erick

vedant

ARYK

ERC721

After the standard ERC-721, came a superior version to it and brought many improvements with it. This new token standard was called ERC-721A. Its main objective is to save a significant amount of gas that is wasted in minting multiple NFTs in a single transaction.

<p>After the standard ERC-721, came a superior version to it and brought many improvements with it. This new token standard was called <a href="https://www.erc721a.org/" target="_blank" rel="noopener noreferrer">ERC-721A</a>. Its main objective is to save a significant amount of gas that is wasted in minting multiple NFTs in a single transaction. This standard was built by <a href="https://www.azuki.com/" target="_blank" rel="noopener noreferrer">Azuki</a> to cut down on the disadvantages of its predecessor and to add on additional much-needed benefits. Therefore, the Azuki contract will allow you to mint numerous NFTs at the same price as a single NFT. Azuki’s partnership with external security consultants ensures that their approach is correct and sound. ERC-721A has been made public in the hope to encourage the community to support and adopt it in order to reduce the carbon footprint and gas costs.</p><p>Gas prices rise rapidly on Ethereum following the popularity of NFT projects. Developers need to adapt and grow accordingly. Azuki aims to build a brand for the dev team that optimizes the contract and enables the community to bear the least amount of gas expenses when minting.&nbsp;</p><p>Let's get to writing our smart contract.</p>

# ERC-721A – The Superior Iteration

After the standard ERC-721, came a superior version to it and brought many improvements with it. This new token standard was called [ERC-721A](https://www.erc721a.org/). Its main objective is to save a significant amount of gas that is wasted in minting multiple NFTs in a single transaction. This standard was built by [Azuki](https://www.azuki.com/) to cut down on the disadvantages of its predecessor and to add on additional much-needed benefits. Therefore, the Azuki contract will allow you to mint numerous NFTs at the same price as a single NFT. Azuki’s partnership with external security consultants ensures that their approach is correct and sound. ERC-721A has been made public in the hope to encourage the community to support and adopt it in order to reduce the carbon footprint and gas costs.

Gas prices rise rapidly on Ethereum following the popularity of NFT projects. Developers need to adapt and grow accordingly. Azuki aims to build a brand for the dev team that optimizes the contract and enables the community to bear the least amount of gas expenses when minting.

Let's get to writing our smart contract.


https://raw.githubusercontent.com/0xmetaschool/Learning-Projects/main/Creating%20NFTs%20using%20different%20token%20standards/3.%20ERC-721A%20%E2%80%93%20The%20Superior%20Iteration/1.%20ERC-721A%20%E2%80%93%20The%20Superior%20Iteration.md

ERC-721A – The Superior Iteration

<p>Much talking, huh? Let's get straight to the practical part of it. Let's look at how to code it.</p><p>The following code is derived from the official GitHub <a href="https://github.com/chiru-labs/ERC721A/blob/main/contracts/ERC721A.sol" target="_blank" rel="noopener noreferrer">repo</a> for ERC721A. Notice the <em>mint</em> function now takes in <em>quantity</em> instead of <em>tokenId.</em> Feel free to play around.</p><pre><code>pragma solidity ^0.8.9;import "erc721a/contracts/ERC721A.sol";contract Azuki is ERC721A {  constructor() ERC721A("Azuki", "AZUKI") {}  function mint(uint256 quantity) external payable {    // _safeMint's second argument now takes in a quantity, not a tokenId.    _safeMint(msg.sender, quantity);  }}</code></pre><p>Even simpler than the golden standard, no?</p>

# Writing an ERC-721A Smart Contract

Much talking, huh? Let's get straight to the practical part of it. Let's look at how to code it.

The following code is derived from the official GitHub [repo](https://github.com/chiru-labs/ERC721A/blob/main/contracts/ERC721A.sol) for ERC721A. Notice the _mint_ function now takes in _quantity_ instead of _tokenId._ Feel free to play around.

```reasonml
pragma solidity ^0.8.9;

import "erc721a/contracts/ERC721A.sol";

contract Azuki is ERC721A {
  constructor() ERC721A("Azuki", "AZUKI") {}
  function mint(uint256 quantity) external payable {
    // _safeMint's second argument now takes in a quantity, not a tokenId.
    _safeMint(msg.sender, quantity);
  }
}
```

Even simpler than the golden standard, no?


https://raw.githubusercontent.com/0xmetaschool/Learning-Projects/main/Creating%20NFTs%20using%20different%20token%20standards/3.%20ERC-721A%20%E2%80%93%20The%20Superior%20Iteration/2.%20Writing%20an%20ERC-721A%20Smart%20Contract.md

Writing A ERC-721A Smart Contract

<p>Azuki has measured the gas costs and prices for mining, where they compared OpenZeppelin’s ERC721Enumerable vs ERC721A which they have documented below. This explains how users are charged an exorbitant amount of gas fee per transaction which adds up to become quite costly.</p><p></p><figure class="table"><table><thead><tr><th><div><strong>NUMBER MINTED</strong></div></th><th><div><strong>GAS USED (ENUMERABLE)</strong></div></th><th><div><strong>GAS USED (ERC721A)</strong></div></th><th><div><strong>GAS SAVED</strong></div></th></tr></thead><tbody><tr><td><div>Mint 1</div></td><td><div>154,814</div></td><td><div>76,690</div></td><td><div><strong>78,124</strong></div></td></tr><tr><td><div>Mint 2</div></td><td><div>270,339</div></td><td><div>78,819</div></td><td><div><strong>191,520</strong></div></td></tr><tr><td><div>Mint 3</div></td><td><div>384,864</div></td><td><div>80,948</div></td><td><div><strong>303,916</strong></div></td></tr><tr><td><div>Mint 4</div></td><td><div>501,389</div></td><td><div>83,077</div></td><td><div><strong>418,312</strong></div></td></tr><tr><td><div>Mint 5</div></td><td><div>616,914</div></td><td><div>85,206</div></td><td><div><strong>531,708</strong></div></td></tr></tbody></table></figure><p></p><p>As a result, ERC-721A has brought forth some optimizations in order to reduce the gas prices, which are explained below.</p><h3><strong>Eliminating (OZ) ERC721Enumerable's Duplicate Storage</strong></h3><p>The mass usage of OZ implementation of IERC721Enumerable includes redundant storage of each token’s metadata. This alien approach optimizes for read functions at a higher cost than write functions which are not desired because users are much less likely to pay for read functions. In addition to this, Azuki’s tokens are serially numbered from 0 which helps them remove redundant storage from the base implementation.</p><h3><strong>Updating Owner Balance Once Per Batch Mint Request</strong></h3><p>The second improvement added by Azuki is the feature to update the owner’s balance once per batch mint request instead of updating per minted NFT. Let us make it simple enough for you to understand. For example, James has 3 tokens and he wants to buy 6 more, in Solidity, it costs gas to update a stored value. So if we are tracking in storage how many tokens James owns, it is cheaper to update James’ holdings from 3 directly to 9 with one update, instead of updating that value 6 times.</p><p>While this is a simple notion, the great majority of bulk mints in the NFT ecosystem have yet to embrace it since the OZ default implementation lacks a batch mint API, and it's tempting to utilize an existing solution without altering it. If your project supports batch mints, we strongly advise you to consider this method.</p><h3><strong>Updating Owner Data Once Per Batch Mint Request</strong></h3><p>This optimization is pretty similar to the previous one. Suppose James want to buy 3 tokens namely token #200, #201, and #202. Instead of declaring James as the owner 3 times, each time costing us gas, instead, we can preserve the owner value just once, implying that James owns all three tokens conceptually. ERC-721A still expects significant net savings from this since it minimizes the amount of gas used at the mint, reducing the severity of concentrated gas surges for the entire ecosystem during the mint season. Not only will NFT mint costs become cheaper for individual transactions, but there will be reduced network congestion and gas price spikes on the Ethereum network during popular collection drops.</p><h2><strong>Collections Utilizing ERC-721A</strong></h2><p>There is a vast variety of collections utilizing ERC-721A including <a href="https://www.kittycryptogang.com/" target="_blank" rel="noopener noreferrer">KittyCryptoGang</a>, <a href="https://www.azuki.com/gallery" target="_blank" rel="noopener noreferrer">Azuki Gallery</a>, and <a href="https://xrabbits.club/" target="_blank" rel="noopener noreferrer">XRabbitsClub</a>. This standard is primarily used to save excessive gas fees with the help of batch mining. ERC-721A reduces wasted storage of token metadata and limits the ownership state updates to only once per batch mint instead of once per minted batch. This results in reduced work required to send write transactions which saves on gas as write is more costly than the read function. Therefore, by reducing the number of write transactions, NFT minting cost is reduced drastically.</p>

# Perks Entailing ERC-721A

Azuki has measured the gas costs and prices for mining, where they compared OpenZeppelin’s ERC721Enumerable vs ERC721A which they have documented below. This explains how users are charged an exorbitant amount of gas fee per transaction which adds up to become quite costly.

**NUMBER MINTED**

**GAS USED (ENUMERABLE)**

**GAS USED (ERC721A)**

**GAS SAVED**

Mint 1

154,814

76,690

**78,124**

Mint 2

270,339

78,819

**191,520**

Mint 3

384,864

80,948

**303,916**

Mint 4

501,389

83,077

**418,312**

Mint 5

616,914

85,206

**531,708**

As a result, ERC-721A has brought forth some optimizations in order to reduce the gas prices, which are explained below.

## Eliminating (OZ) ERC721Enumerable's Duplicate Storage

The mass usage of OZ implementation of IERC721Enumerable includes redundant storage of each token’s metadata. This alien approach optimizes for read functions at a higher cost than write functions which are not desired because users are much less likely to pay for read functions. In addition to this, Azuki’s tokens are serially numbered from 0 which helps them remove redundant storage from the base implementation.

## Updating Owner Balance Once Per Batch Mint Request

The second improvement added by Azuki is the feature to update the owner’s balance once per batch mint request instead of updating per minted NFT. Let us make it simple enough for you to understand. For example, James has 3 tokens and he wants to buy 6 more, in Solidity, it costs gas to update a stored value. So if we are tracking in storage how many tokens James owns, it is cheaper to update James’ holdings from 3 directly to 9 with one update, instead of updating that value 6 times.

While this is a simple notion, the great majority of bulk mints in the NFT ecosystem have yet to embrace it since the OZ default implementation lacks a batch mint API, and it's tempting to utilize an existing solution without altering it. If your project supports batch mints, we strongly advise you to consider this method.

## Updating Owner Data Once Per Batch Mint Request

This optimization is pretty similar to the previous one. Suppose James want to buy 3 tokens namely token #200, #201, and #202. Instead of declaring James as the owner 3 times, each time costing us gas, instead, we can preserve the owner value just once, implying that James owns all three tokens conceptually. ERC-721A still expects significant net savings from this since it minimizes the amount of gas used at the mint, reducing the severity of concentrated gas surges for the entire ecosystem during the mint season. Not only will NFT mint costs become cheaper for individual transactions, but there will be reduced network congestion and gas price spikes on the Ethereum network during popular collection drops.

## Collections Utilizing ERC-721A

There is a vast variety of collections utilizing ERC-721A including [KittyCryptoGang](https://www.kittycryptogang.com/), [Azuki Gallery](https://www.azuki.com/gallery), and [XRabbitsClub](https://xrabbits.club/). This standard is primarily used to save excessive gas fees with the help of batch mining. ERC-721A reduces wasted storage of token metadata and limits the ownership state updates to only once per batch mint instead of once per minted batch. This results in reduced work required to send write transactions which saves on gas as write is more costly than the read function. Therefore, by reducing the number of write transactions, NFT minting cost is reduced drastically.


https://raw.githubusercontent.com/0xmetaschool/Learning-Projects/main/Creating%20NFTs%20using%20different%20token%20standards/3.%20ERC-721A%20%E2%80%93%20The%20Superior%20Iteration/3.%20Perks%20Entailing%20ERC-721A.md

Perks Entailing ERC-721A

<p>ERC-721 and ERC-721A are both prominent standards that are appreciated for their unique characteristics; which one you choose is a question of personal preference. This choice should be made depending on the frequency of your transactions and your current minting framework.Let us make this process easier for you:</p><p></p><figure class="table"><table><thead><tr><th><div><strong>Feature</strong></div></th><th><div><strong>ERC-721</strong></div></th><th><div><strong>ERC-721A</strong></div></th></tr></thead><tbody><tr><td><div>Token Creation</div></td><td><div>Single Contract</div></td><td><div>Single Contract</div></td></tr><tr><td><div>Limitation</div></td><td><div>Limited to Non-Fungible Tokens</div></td><td><div>Limited to Non-Fungible Tokens</div></td></tr><tr><td><div>Ease of Use</div></td><td><div>Expensive and time consuming as only single operation allowed for transaction</div></td><td><div>Cost-Effective and time-efficient. Batch minting at the cost of single operation</div></td></tr><tr><td><div>Efficiency</div></td><td><div>Reduced blockchain efficiency due to increased code redundancy</div></td><td><div>Increased blockchain efficiency due to serially numbered tokens that eliminate code redundancy</div></td></tr><tr><td><div>Blockchain Network</div></td><td><div>Ethereum</div></td><td><div>Ethereum</div></td></tr><tr><td><div>Balance Updates</div></td><td><div>Balance updates per minted NFT</div></td><td><div>Balance updates once per batch mint request</div></td></tr><tr><td><div>Gas Consumption</div></td><td><div>High, as gas levied per every NFT minting operation</div></td><td><div>Low, as gas levied only once per batch operation</div></td></tr><tr><td><div>Data Updates</div></td><td><div>Owner data updated per minted NFT</div></td><td><div>Owner data updated once per batch mint request</div></td></tr><tr><td><div>Severity of Concentrated Gas Spikes</div></td><td><div>High</div></td><td><div>Low</div></td></tr></tbody></table></figure><p></p><h3><strong>Test Your Knowledge</strong></h3><p>ERC-721A token standard is an optimization of?<br>(a). ERC-20<br>(b). ERC-721<br>(c). ERC-1155<br>(d). Is a distinct standard in itself</p>

# Settling the Debate Between ERC-721 and ERC-721A

ERC-721 and ERC-721A are both prominent standards that are appreciated for their unique characteristics; which one you choose is a question of personal preference. This choice should be made depending on the frequency of your transactions and your current minting framework.Let us make this process easier for you:

</p>
<figure class="table">
    <table>
        <thead>
            <tr>
                <th>
                    <strong>Feature</strong>
                </th>
                <th>
                    <strong>ERC-721</strong>
                </th>
                <th>
                    <strong>ERC-721A</strong>
                </th>
            </tr>
        </thead>
        <tbody>
            <tr>
                <td>
                    Token Creation
                </td>
                <td>
                    Single Contract
                </td>
                <td>
                    Single Contract
                </td>
            </tr>
            <tr>
                <td>
                    Limitation
                </td>
                <td>
                    Limited to Non-Fungible Tokens
                </td>
                <td>
                    Limited to Non-Fungible Tokens
                </td>
            </tr>
            <tr>
                <td>
                    Ease of Use
                </td>
                <td>
                    Expensive and time consuming as only single operation allowed for transaction
                </td>
                <td>
                    Cost-Effective and time-efficient. Batch minting at the cost of single operation
                </td>
            </tr>
            <tr>
                <td>
                    Efficiency
                </td>
                <td>
                    Reduced blockchain efficiency due to increased code redundancy
                </td>
                <td>
                    Increased blockchain efficiency due to serially numbered tokens that eliminate code redundancy
                </td>
            </tr>
            <tr>
                <td>
                    Blockchain Network
                </td>
                <td>
                    Ethereum
                </td>
                <td>
                    Ethereum
                </td>
            </tr>
            <tr>
                <td>
                    Balance Updates
                </td>
                <td>
                    Balance updates per minted NFT
                </td>
                <td>
                    Balance updates once per batch mint request
                </td>
            </tr>
            <tr>
                <td>
                    Gas Consumption
                </td>
                <td>
                    High, as gas levied per every NFT minting operation
                </td>
                <td>
                    Low, as gas levied only once per batch operation
                </td>
            </tr>
            <tr>
                <td>
                    Data Updates
                </td>
                <td>
                    Owner data updated per minted NFT
                </td>
                <td>
                    Owner data updated once per batch mint request
                </td>
            </tr>
            <tr>
                <td>
                    Severity of Concentrated Gas Spikes
                </td>
                <td>
                    High
                </td>
                <td>
                    Low
                </td>
            </tr>
        </tbody>
    </table>
</figure>


https://raw.githubusercontent.com/0xmetaschool/Learning-Projects/main/Creating%20NFTs%20using%20different%20token%20standards/3.%20ERC-721A%20%E2%80%93%20The%20Superior%20Iteration/4.%20Settling%20the%20Debate%20Between%20ERC-721%20and%20ERC-721A.md

Settling the Debate Between ERC-721 and ERC-721A

Samuel Aondo

saad

Phewww!! Your wait is finally over! In this section, we'll be discussing the most advanced token standard, ERC-1155.

<p></p><figure class="image"><div class="se-component se-image-container __se__float-none" contenteditable="false"><figure class="image" style="margin: 0px;"><img src="https://metaschool.s3-ap-southeast-1.amazonaws.com/images/FIFOK7b5dFbKsM3j4bKmnF6IkFbkEI7pFkm75Cm2.gif" data-origin="," alt="" data-proportion="true" data-align="none" data-file-name="FIFOK7b5dFbKsM3j4bKmnF6IkFbkEI7pFkm75Cm2.gif" data-file-size="0" data-rotate="" data-rotatex="" data-rotatey="" data-size="," data-percentage="auto,auto" style="" data-index="0"></figure></div></figure><p></p><p>ERC-1155 is a brand-new token standard that strives to combine the finest features of prior token standards to build a fungibility-agnostic, gas-efficient token contract. This standard eliminates the drawbacks and limitations of its predecessors and builds upon their success. The distinctive feature that makes it stand out is the fact that it uses a single smart contract to represent multiple types of tokens (both fungible and non-fungible) at once.</p><p>The standard's blisteringly quick speed is one of its main selling factors. This speed is accomplished by combining many token IDs into a single transaction, allowing for rapid transfer of cash and tokens. This has a lower impact on the blockchain and speeds up transactions. This method is very useful for applications that require a large number of tokens. Instead of creating separate contracts for each token type, a single ERC1155 token contract might include the whole system state, reducing deployment costs and complexity.</p><p>Although it looks quite similar to ERC-721 at an initial glance because it contains an extra id parameter for the identification of the token whose balance you wish to check. But in ERC-721 and ERC-721A each token is NFT and it either exists or not. On the contrary, in ERC 1155 each token id has its own balance in an ERC1155 account, and non-fungible tokens are produced by minting a single one.</p><p></p><figure class="image"><div class="se-component se-image-container __se__float-none" contenteditable="false"><figure class="image" style="margin: 0px;"><img src="https://metaschool.s3-ap-southeast-1.amazonaws.com/images/ZaMsQSU4fAFqS3wRFyOloSBAUgPnlvCWquzvfUKu.gif" data-origin="," alt="" data-proportion="true" data-align="none" data-file-name="ZaMsQSU4fAFqS3wRFyOloSBAUgPnlvCWquzvfUKu.gif" data-file-size="0" data-rotate="" data-rotatex="" data-rotatey="" data-size="," data-percentage="auto,auto" style="" data-index="1"></figure></div></figure><p></p>

# ERC-1155 – One Above All

![](https://metaschool.s3-ap-southeast-1.amazonaws.com/images/FIFOK7b5dFbKsM3j4bKmnF6IkFbkEI7pFkm75Cm2.gif)

ERC-1155 is a brand-new token standard that strives to combine the finest features of prior token standards to build a fungibility-agnostic, gas-efficient token contract.

This standard eliminates the drawbacks and limitations of its predecessors and builds upon their success. The distinctive feature that makes it stand out is the fact that it uses a single smart contract to represent multiple types of tokens (both fungible and non-fungible) at once.

The standard's blisteringly quick speed is one of its main selling factors. This speed is accomplished by combining many token IDs into a single transaction, allowing for rapid transfer of cash and tokens. This has a lower impact on the blockchain and speeds up transactions.

This method is very useful for applications that require a large number of tokens. Instead of creating separate contracts for each token type, a single ERC1155 token contract might include the whole system state, reducing deployment costs and complexity.

Although it looks quite similar to ERC-721 at an initial glance because it contains an extra id parameter for the identification of the token whose balance you wish to check.

But in ERC-721 and ERC-721A each token is NFT and it either exists or not. On the contrary, in ERC 1155 each token id has its own balance in an ERC1155 account, and non-fungible tokens are produced by minting a single one.


https://raw.githubusercontent.com/0xmetaschool/Learning-Projects/main/Creating%20NFTs%20using%20different%20token%20standards/4.%20ERC-1155%20%E2%80%93%20One%20Above%20All/1.%20ERC-1155%20%E2%80%93%20One%20Above%20All.md

ERC-1155 – One Above All

<p>Here comes the most exciting part of this article i.e. the comparison between these three token standards. What do you think, who's gonna win the trust and secure more confidence in the industry? Any guesses?</p><div class="se-component se-image-container __se__float- __se__float-none" contenteditable="false"><figure style="margin: 0px;"><img src="https://github.com/ismailvohra/creating-nfts-using-different-token-standards/raw/main/assets/think.gif" data-origin="," alt="" data-proportion="true" data-align="none" data-file-name="think.gif" data-file-size="0" data-rotate="" data-rotatex="" data-rotatey="" data-size="," data-percentage="auto,auto" style="" data-index="0"></figure></div><p>The following chart details the similarities and differences between ERC-721, ERC-721A and ERC-1155:</p><p></p><figure class="table"><table><thead><tr><th><div><strong>Technical Specifications</strong></div></th><th><div><strong>ERC-721</strong></div></th><th><div><strong>ERC-721A</strong></div></th><th><div><strong>ERC-1155</strong></div></th></tr></thead><tbody><tr><td><div>Fungibile and Non-Fungible</div></td><td><div>Non-Fungible token creation</div></td><td><p>Non-Fungible token creation</p><p>&nbsp;</p></td><td><div>Non-Fungible and Fungible token creation</div></td></tr><tr><td><div>Blockchain Network</div></td><td><div>Ethereum</div></td><td><div>Ethereum</div></td><td><div>Ethereum</div></td></tr><tr><td><div>Batch Transfers</div></td><td><div>Supports single token transfer at a time</div></td><td><div>Supports single token transfer at a time</div></td><td><div>Supports batch transfers of various token IDs in a single token transaction</div></td></tr><tr><td><div>Smart Contracts</div></td><td><div>Requires a new contract for each type of ERC-721 contract</div></td><td><div>Requires a new contract for each type of ERC-721 contract</div></td><td><div>Requires single contract for infinite token types</div></td></tr><tr><td><div>Localization</div></td><td><div>Single Language Supported</div></td><td><div>Single Language Supported</div></td><td><div>Universal tokenization: localization support for languages of all metadata, including names and descriptions</div></td></tr><tr><td><div>Legacy Metadata</div></td><td><div>Metadata in the form of symbols and names</div></td><td><div>Metadata in the form of symbols and names</div></td><td><div>Metadata in the form of web or IPFS</div></td></tr><tr><td><div>ID Substitution</div></td><td><div>Supports only static metadata, each token id have metadata URI stored on smart contract</div></td><td><div>Supports only static metadata, each token id have metadata URI stored on smart contract</div></td><td><div>Smart contracts can point to various token URIs without accumulating additional data</div></td></tr><tr><td><div>Rich Event Logs</div></td><td><div>Emits Transfers and Approvals</div></td><td><div>Emits Transfers and Approvals</div></td><td><div>Includes standardized events such as mints, burns and transfers</div></td></tr></tbody></table></figure><p></p>

# ERC-721 vs. ERC-721A vs. ERC-1155

Here comes the most exciting part of this article i.e. the comparison between these three token standards. What do you think, who's gonna win the trust and secure more confidence in the industry? Any guesses?

The following chart details the similarities and differences between ERC-721, ERC-721A and ERC-1155:

</p>
<figure class="table">
    <table>
        <thead>
            <tr>
                <th>
                    <strong>Technical Specifications</strong>
                </th>
                <th>
                    <strong>ERC-721</strong>
                </th>
                <th>
                    <strong>ERC-721A</strong>
                </th>
                <th>
                    <strong>ERC-1155</strong>
                </th>
            </tr>
        </thead>
        <tbody>
            <tr>
                <td>
                    Fungibile and Non-Fungible
                </td>
                <td>
                    Non-Fungible token creation
                </td>
                <td>
                    <p>
                        Non-Fungible token creation
                    </p>
                    <p>
                        &nbsp;
                    </p>
                </td>
                <td>
                    Non-Fungible and Fungible token creation
                </td>
            </tr>
            <tr>
                <td>
                    Blockchain Network
                </td>
                <td>
                    Ethereum
                </td>
                <td>
                    Ethereum
                </td>
                <td>
                    Ethereum
                </td>
            </tr>
            <tr>
                <td>
                    Batch Transfers
                </td>
                <td>
                    Supports single token transfer at a time
                </td>
                <td>
                    Supports single token transfer at a time
                </td>
                <td>
                    Supports batch transfers of various token IDs in a single token transaction
                </td>
            </tr>
            <tr>
                <td>
                    Smart Contracts
                </td>
                <td>
                    Requires a new contract for each type of ERC-721 contract
                </td>
                <td>
                    Requires a new contract for each type of ERC-721 contract
                </td>
                <td>
                    Requires single contract for infinite token types
                </td>
            </tr>
            <tr>
                <td>
                    Localization
                </td>
                <td>
                    Single Language Supported
                </td>
                <td>
                    Single Language Supported
                </td>
                <td>
                    Universal tokenization: localization support for languages of all metadata, including names and descriptions
                </td>
            </tr>
            <tr>
                <td>
                    Legacy Metadata
                </td>
                <td>
                    Metadata in the form of symbols and names
                </td>
                <td>
                    Metadata in the form of symbols and names
                </td>
                <td>
                    Metadata in the form of web or IPFS
                </td>
            </tr>
            <tr>
                <td>
                    ID Substitution
                </td>
                <td>
                    Supports only static metadata, each token id have metadata URI stored on smart contract
                </td>
                <td>
                    Supports only static metadata, each token id have metadata URI stored on smart contract
                </td>
                <td>
                    Smart contracts can point to various token URIs without accumulating additional data
                </td>
            </tr>
            <tr>
                <td>
                    Rich Event Logs
                </td>
                <td>
                    Emits Transfers and Approvals
                </td>
                <td>
                    Emits Transfers and Approvals
                </td>
                <td>
                    Includes standardized events such as mints, burns and transfers
                </td>
            </tr>
        </tbody>
    </table>
</figure>


https://raw.githubusercontent.com/0xmetaschool/Learning-Projects/main/Creating%20NFTs%20using%20different%20token%20standards/4.%20ERC-1155%20%E2%80%93%20One%20Above%20All/2.%20ERC-721%20vs.%20ERC-721A%20vs.%20ERC-1155.md

ERC-721 vs. ERC-721A vs. ERC-1155

<p>The striking thing about this standard is that it covers both fungible and non-fungible tokens, which means that it possesses a great deal of flexibility. This flexibility makes it ideal for games for example in-game coins would likely be fungible while a plot of virtual land would be non-fungible. As it was created by the people behind Minecraft, it is only natural that the standard is focused on the gaming industry. In order to be deemed to be used for in-game payments, a standard must be able to cater to fungible and non-fungible items both. Only ERC 1155 fits the description of a perfect standard.</p><p>According to Radomski, ERC-1155 co-creator ‘‘It’s really like a vending machine for NFTs and fungible tokens, with advanced usability features and functionality like batch transfers to enable efficient, large-scale blockchain games and apps.” It is used to give game developers new tools to gamify and add real economies to their games using blockchain. The primary use case for ERC 1155 is blockchain-based games. ERC 1155 is preferred in online multiplayer games because mainstream games need an evolved token with an updated standard that only comes in the form of ERC 1155. Existing token standards and designs are flawed and unsuitable for gaming because games contain hundreds to thousands of items and deploying a separate contract for each and every item to the blockchain is impossible. ERC-1155 proposes a novel method for the token definition. Items are now held in a single contract with as little data as possible to identify them from other tokens. The contract state contains all of the behavior guiding the collection, as well as configuration data per Token ID.</p>

# ERC-1155 Unique Use Cases and When it is Preferred

The striking thing about this standard is that it covers both fungible and non-fungible tokens, which means that it possesses a great deal of flexibility.

This flexibility makes it ideal for games for example in-game coins would likely be fungible while a plot of virtual land would be non-fungible.

As it was created by the people behind Minecraft, it is only natural that the standard is focused on the gaming industry. In order to be deemed to be used for in-game payments, a standard must be able to cater to fungible and non-fungible items both. Only ERC 1155 fits the description of a perfect standard.

According to Radomski, ERC-1155 co-creator ‘‘It’s really like a vending machine for NFTs and fungible tokens, with advanced usability features and functionality like batch transfers to enable efficient, large-scale blockchain games and apps.”

It is used to give game developers new tools to gamify and add real economies to their games using blockchain.

The primary use case for ERC 1155 is blockchain-based games. ERC 1155 is preferred in online multiplayer games because mainstream games need an evolved token with an updated standard that only comes in the form of ERC 1155.

Existing token standards and designs are flawed and unsuitable for gaming because games contain hundreds to thousands of items and deploying a separate contract for each and every item to the blockchain is impossible.

ERC-1155 proposes a novel method for the token definition. Items are now held in a single contract with as little data as possible to identify them from other tokens. The contract state contains all of the behavior guiding the collection, as well as configuration data per Token ID.


https://raw.githubusercontent.com/0xmetaschool/Learning-Projects/main/Creating%20NFTs%20using%20different%20token%20standards/4.%20ERC-1155%20%E2%80%93%20One%20Above%20All/3.%20ERC-1155%20Unique%20Use%20Cases%20and%20When%20it%20is%20Preferred.md

ERC-1155 Unique Use Cases and When it is Preferred

<p>ERC-1155 and games are made for each other. This standard is specifically crafted to cater to the needs of in-game purchases.ERC1155 is a new way to create semi-fungible tokens. These are new forms of tokens that combine various attributes from previous token standards. Consider it a case of getting the best of both worlds. Consider the following example: you may design a shop voucher - a fungible token – that retains its worth until it is redeemed. The coupon has no value when it is redeemed, and it cannot be traded like a typical fungible token. As a result, the used coupon becomes unique, containing information about the item redeemed, the client, the price, and so on. As a result, it is no longer fungible. A semi-fungible token standard like ERC1155, on the other hand, may express both properties.</p><p>Even though it doesn't garner quite as much attention right now, the ERC-1155 standard has some non-gaming applications. It may be used to tokenize a wide range of digitally represented items, including trophies, charitable donations, incentive programs, discount coupons, and concert tickets.</p><p>It has been utilized by <a href="https://www.gdac.com/" target="_blank" rel="noopener noreferrer">GDAC</a> and <a href="https://kriptomat.io/" target="_blank" rel="noopener noreferrer">Kriptomat</a> to both gamify the trading experience and fuel loyalty programs.</p><p>Multiple games are using ERC-155 as their go-to standard. <a href="https://enjin.io/" target="_blank" rel="noopener noreferrer">Enjin</a>, <a href="https://www.sandbox.game/en/" target="_blank" rel="noopener noreferrer">The Sandbox</a>, and <a href="https://horizon.io/" target="_blank" rel="noopener noreferrer">Horizon Blockchain Games</a> have already deployed them there.is a new standard for representing virtual items on the Ethereum blockchain that allows the creation of multiple types of tokens in the same contract. Now with the advent of the metaverse, an increasing number of games are employing ERC-1155. Horizon Games (developers of Skyweaver) and Pixowl (developers of The Sandbox) collaborated on the standard, as did the Enjin team, who have helped bring a slew of additional games on board in terms of acceptance.</p><p>There are already 30+ Enjin-based ERC-1155s in development that have officially collaborated with Enjin, spanning a number of gaming genres. <a href="https://www.ageofrustgame.com/" target="_blank" rel="noopener noreferrer">Age of Rust</a>, <a href="https://www.9livesarena.com/" target="_blank" rel="noopener noreferrer">9 Lives Arena</a>, <a href="https://spacemisfits.com/" target="_blank" rel="noopener noreferrer">Space Misfits</a>, and <a href="https://lostrelics.io/" target="_blank" rel="noopener noreferrer">Lost Relics</a> are all worth checking out.</p><p>Now that we have explored ERC-721, ERC-721A, and ERC-1155, it might be your curious question that which token standard you should prefer to create your smart contracts. Well, there is not a binary answer to it. It completely depends on the use-case that you're trying to achieve. You need to critically invest your time and think about the pros and cons of adopting one standard against the others. It is in fact a nice confusion to have in mind as it will allow you to explore the limitations and work towards better implementation plans of your smart contracts as well. So yeah, it is what it is! 🤷‍♂️</p><p>&nbsp;</p><h3><strong>Test Your Knowledge</strong></h3><p>ERC-1155 token standard supports the following token types?<br>(a). Fungible Tokens<br>(b). Non-Fungible Tokens<br>(c). Semi-Fungible Tokens<br>(d). of the Above<br><br><strong>Final Thoughts</strong></p><p>We went through the fundamentals of NFTs and common industry standards, as well as their quick introduction and comprehensive characteristics, in this tutorial. In order to assist you to make an educated decision, we also explained how to implement your own smart contract, as well as present and future uses for these standards. We hope you found this post to be useful in this regard. Let us know which one was your favorite below and as usual happy coding!</p>

# ERC-1155 and Mainstream Collections

ERC-1155 and games are made for each other. This standard is specifically crafted to cater to the needs of in-game purchases.

ERC1155 is a new way to create semi-fungible tokens. These are new forms of tokens that combine various attributes from previous token standards. Consider it a case of getting the best of both worlds.

Look at the following example 👇🏼

You may design a shop voucher - a fungible token – that retains its worth until it is redeemed. The coupon has no value when it is redeemed, and it cannot be traded like a typical fungible token.

As a result, the used coupon becomes unique, containing information about the item redeemed, the client, the price, and so on. As a result, it is no longer fungible. A semi-fungible token standard like ERC1155, on the other hand, may express both properties.

Even though it doesn't garner quite as much attention right now, the ERC-1155 standard has some non-gaming applications. It may be used to tokenize a wide range of digitally represented items, including trophies, charitable donations, incentive programs, discount coupons, and concert tickets.

It has been utilized by [GDAC](https://www.gdac.com/) and [Kriptomat](https://kriptomat.io/) to both gamify the trading experience and fuel loyalty programs.

Multiple games are using ERC-155 as their go-to standard. [Enjin](https://enjin.io/), [The Sandbox](https://www.sandbox.game/en/), and [Horizon Blockchain Games](https://horizon.io/) have already deployed them there.is a new standard for representing virtual items on the Ethereum blockchain that allows the creation of multiple types of tokens in the same contract.

Now with the advent of the metaverse, an increasing number of games are employing ERC-1155. Horizon Games (developers of Skyweaver) and Pixowl (developers of The Sandbox) collaborated on the standard, as did the Enjin team, who have helped bring a slew of additional games on board in terms of acceptance.

There are already 30+ Enjin-based ERC-1155s in development that have officially collaborated with Enjin, spanning a number of gaming genres. [Age of Rust](https://www.ageofrustgame.com/), [9 Lives Arena](https://www.9livesarena.com/), [Space Misfits](https://spacemisfits.com/), and [Lost Relics](https://lostrelics.io/) are all worth checking out.

Now that we have explored ERC-721, ERC-721A, and ERC-1155, it might be your curious question that which token standard you should prefer to create your smart contracts. Well, there is not a binary answer to it. It completely depends on the use-case that you're trying to achieve.

You need to critically invest your time and think about the pros and cons of adopting one standard against the others. It is in fact a nice confusion to have in mind as it will allow you to explore the limitations and work towards better implementation plans of your smart contracts as well. So yeah, it is what it is! 🤷‍♂️

**Final Thoughts**

We went through the fundamentals of NFTs and common industry standards, as well as their quick introduction and comprehensive characteristics, in this tutorial. In order to assist you to make an educated decision, we also explained how to implement your own smart contract, as well as present and future uses for these standards. We hope you found this post to be useful in this regard. Let us know which one was your favorite below and as usual happy coding!

## ⚒️ A small yet important request:

This is a 100% open-source project like all the other projects on our platform. You can find the tutorial markdown files [here](https://github.com/0xmetaschool/Learning-Projects/tree/main/Creating%20NFTs%20using%20different%20token%20standards). If you find any issues in the course, please feel free to resolve it. We, at Metaschool, love love love contributions by our community and acknowledge the contributors on our [Discord](https://discord.com/invite/vbVMUwXWgc) and GitHub, too.

While you’re contributing:

1. Don’t forget to star ⭐️ our repository. We will be very thankful! ❤️
2. We are a completely free platform and we aim to stay the same, so please consider following us on [X](https://bit.ly/token-stnd-twitter) and [LinkedIn](https://bit.ly/token-stnd-linkedin) as well. 🫶



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ERC-1155 and Mainstream Collections

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Introduction

ERC721

ERC-721A – The Superior Iteration

ERC-1155 – One Above All

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