ERC721 vs. ERC721A

Maciej Zieliński

29 Mar 2022
ERC721 vs. ERC721A

Technology can be a great solution for many businesses and companies. Unfortunately, one of the unfortunate side effects is the amount of various technical jargon, which may be unintelligible to the average person. For the end-user, NFT often means little more than a decentralized collectors' item or a work of digital art. You can enjoy this industry without understanding how it works. But the trends in blockchain technology can be fascinating even for those who are not involved with creating it. Why are ERC721 and ERC721A so important in NFT? What makes it special and why should we learn about this technology? We're writing about this below!

What is ERC721?

Although blockchain technology is decentralized, we need a common language which will allow us to understand the data contained within it. As such, token standards like ERC721 become essential. It is a standard which works in a similar way to how all ports or plugs on various devices work. It is worth noting, for example, that formats such as PNG i JPEG, which are commonly associated with NFT, are by themselves image standards.
ERC721 is an extremely popular token standard for creating non-fungible tokens – NFT – on blockchains, such as Ethereum and Polygon. The letter ‘E’ in ‘ERC721’ stands for ‘Ethereum’ and is not the NFT standard that runs on blockchains that are incompatible with Ethereum portfolios such as Solana and Tezos.

​What makes ERC721 compliant tokens useful?

Below we outline some of the advantages of this solution:

  • Each token is unique (previously mentioned non-fungibility)
  • Each token can be transferred or sold
  • Owners can authorize other smart contracts to manage tokens

In addition, each of them is crucial to ensuring that NFT markets, such as OpenSea and LooksRare, can operate as intended. It should be pointed out that smart contracts are simply applications that live within blockchain technology. Seems complicated? It can be described in an even simpler way: ERC721 is a standardized way of creating unique blockchain tokens, which can be traded at markets.

​What is ERC721A?

Software developers in crypto typically use existing code libraries to simplify the development process of a project. When you write a code that's in the blockchain, there's even more pressure to use a battle-proven, existing code wherever possible, because blockchain technology prevents any code editing! In the NFT sector, a single open source code was widely accepted in order to enable the use of ERC721. Then there was the “Azuki” project, which quickly gained recognition in the NFT sector. In addition to the NFT issue itself, the project has created a new implementation of ERC721A.
The implementation of ERC721A is not meant to change the token standard. Its main purpose is to fit the token perfectly, but this task requires a number of other standards to be met, as opposed to ERC721 which has been used to date.
This has led to the reduction of the amount of gas needed to mint new NFT (especially those that are minted in batches).
The gas costs incurred in transferring NFT based on ERC721A to other persons at the original owner's prices are slightly higher. Overall, the gas savings that ERC721A can provide compared to ERC721 are excellent, but this solution cannot be implemented everywhere. For example, entities that do not mint NFT in bulk will still spend a significant amount of gas if we consider the transfer costs.

Let us remember that NFT provides many limitless possibilities not only for art, music, or sports. It is important to know and understand ERC721 and ERC721A, as this allows us to understand what NFT really is from its very basics. This makes us more aware of the direction in which this sector is developing. It is worth noting that while both implementations are important, they are neither the first nor last elements of NFT. They are the benchmark to follow.

How does ERC721A work?

ERC721A adopts specific conditions which then affect the smart contract project. This impact makes the following things happen:

  • Token IDs should always grow steadily – starting from zero. Currently, many NFT projects fulfill this condition.
  • The reduction of the gas costs related to minting NFT is the most important part of NFT production.

With these assumptions, ERC721A makes the following optimization of contracts:

  • Reduces the unused space, which is used to store metadata from tokens.
  • Limits ownership to one coin from the entire NFT batch.

Why is ERC721A so important?

Because it allows us to understand how high the gas charges really are, and what they result from! Reducing your work to sending transactions saves energy. At this point, we should emphasize that blockchain generates 2 types of transactions – reads and writes.

  • Write – occurs when we are doing something in a blockchain and its condition changes (for example, we sell NFT).
  • Read – it can be said that this is a review of the transaction file.

Users who use blockchain technology incur higher write costs than read costs. Therefore, if we reduce the pool of write information or transaction transfer requirements, we will reduce the cost of minting NFT.

What risks are involved with using ERC721A contracts for generating multiple NFT transactions?

TransferFrom and safeTransferFrom transactions cost more gas, which means that NFT can cost more from the moment of its minting. We should emphasize that using ERC721A leads to an increase in performance without the need to set owners of particular token ID.

For example, in the picture below there are two calls to mint a batch, one by Marcus to mint chips #100, #101, and #102 in one call, and the other by Brutus to mint chips #103 and #104

The above diagram shows that ERC721A must set up the property metadata twice, instead of 5 times – once for the Marcus package and once for the Brutus package. This is not so easy because by transferring a tokenID that does not have an owner address, the contract must create actions that include all tokenID’s in order to verify the original NFT owner. This is because the original owner has the right to move the token and set it to a new entity. Below we present a graph associated with this:


The method of reading this chart is as follows: first move to the x-axis and then to the y-axis, for example:

  • „Mint a batch of 1 NFT, and then transfer tokenID 0”,
  • „Mint a batch 3 of NFT, and then transfer tokenID 1”
  • „Mint a batch 5 of NFT, and then transfer tokenID 4”

The above results indicate that moving token IDs in the middle of a larger mint batch (i.e. t1, t2) costs more than moving token IDs at the end of the batch (i.e. t0, t4).

How to minimize the cost of transferring an entire batch of NFT?

You can minimize costs if you are always minting the maximum allowed number of NFT when releasing an entire batch. In addition – when moving a batch, it is important to start a cycle with tokens of an ODD number in an ascending manner.
Examples of NFT projects using the ERC721A contract
Here is a list of projects, which are currently using the ERC721A contract:

  • @AzukiZen
  • @cerealclubnft
  • @TheLostGlitches
  • @standardweb3
  • @KittyCryptoGang
  • @XRabbitsClub
  • @WhaleTogether
  • @pixelpiracynft
  • @dastardlyducks
  • @MissMetaNFT
  • @StarcatchersNFT
  • @LivesOfAsuna
  • @richsadcatnft
  • @themonkeypoly
  • @womenofcrypto_
  • @TravelToucans
  • @HuhuNFT

Are ERC721A contracts still considered to be NFT transactions?

Of course. ERC721A contracts are NFT. Any contract that implements the ERC721 token standard, or the ERC1155 interfaces is seen as non-fungible or semi-fungible tokens. To put it simply, ERC721A is an extension and optimization of the previous version, the ERC721. The ERC721A contract is a very good idea which allows for saving money on gas in a given community, while at the same time protecting the Ethereum network from unnecessary workload.

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What is Account Abstraction?


10 Nov 2023
What is Account Abstraction?

Account abstraction is a new way of thinking about how users interact with blockchains. Instead of using traditional externally owned accounts (EOAs), account abstraction allows users to create and manage their accounts using smart contracts. This has a number of potential benefits, including improved security, enhanced privacy, and increased flexibility.

What is account abstraction?

Account abstraction is a concept that, at its core, aims to simplify the user's interaction with blockchain networks. It is a transformative approach that seeks to mask the technicalities of blockchain operations from end-users. It is making transactions as straightforward as sending an email. Account Abstr. allows users to interact with the blockchain without worrying about the underlying technical details.

How does account abstraction differ from the traditional model?

In the traditional account model, each user has an EOA. EOAs are controlled by private keys, which must be kept secret in order to protect the user's funds. Acc. abstraction allows users to create and manage their accounts using smart contracts.

Historical Context

The journey towards acc. abstraction began with the first generation of blockchain technologies, characterized by their "one-size-fits-all" approach to account management. Bitcoin, for instance, introduced the concept of accounts and transactions in a form that was accessible to tech-savvy individuals but remained perplexing to the layperson. Ethereum expanded on this by introducing smart contracts, which opened the door to programmable transactions but did not alter the fundamental account structure. The idea of acc. abstraction has been discussed in the Ethereum community for several years as a part of various Ethereum Improvement Proposals (EIPs), particularly as a feature to be potentially implemented in Ethereum 2.0. It is a direct response to the need for a more versatile and user-centric design that can cater to a broader audience and spur the widespread adoption of blockchain technology.

The Technicalities of Account Abstraction

Account abstraction is not merely a theoretical construct but a technical innovation with specific mechanisms underpinning its operation. In essence, it alters the way transactions are initiated and executed within a blockchain network.

How Account Abstraction Works

Under traditional blockchain models, initiating a transaction involves an externally owned account (EOA) signing a transaction with a private key. This transaction is then broadcast to the network for validation and inclusion in the blockchain. Account abstraction, however, replaces this process with a more flexible one. Here, every account is a smart contract, and transactions are messages sent through these contracts. These smart contracts can encode complex rules for transaction validation, beyond what EOAs can do, such as multi-signature requirements or conditional transactions based on certain triggers.

The technical crux of account abstraction lies in the smart contract’s ability to define its own conditions for transaction execution. This means that user accounts can have unique security protocols or automated operations without the user needing to understand the underlying smart contract code.

Hey! Are you interested in the latest technologies in the blockchain area? be sure to read the article 'Top Zero-Knowledge Proof Projects to watch in 2023'

The Benefits of Account Abstraction

The implications of account abstraction are profound, offering a range of benefits that can enhance the blockchain experience for users and developers alike.

Improved User Experience

One of the most significant advantages of account abstraction is the improvement it brings to user experience. By abstracting away the complexities of key management and transaction rules, it presents a more intuitive interface for users.

Enhanced Security Features

Account abstraction also allows for the implementation of advanced security measures. Since each account can define its own logic, users can tailor their security settings to their specific needs. For instance, one might set up an account that requires additional verification for transactions exceeding a certain value or restricts withdrawals to certain addresses.

Future Implications

The future implications of account abstraction are vast. As the technology matures, it could become a standard feature of blockchain networks, potentially making the current distinction between user accounts and smart contracts obsolete. This could lead to a new wave of blockchain applications that are both powerful and accessible, bringing us closer to the vision of blockchain technology as a seamless part of everyday life.

Challenges and Considerations

Technical Limitations

One of the primary technical challenges of Acc. abstraction lies in its integration with existing blockchain protocols. Current networks are optimized for the EOA model, and introducing a new account structure necessitates significant changes to the core protocol. This includes modifications to the way transactions are propagated in the network, how gas fees are calculated, and how the state of the blockchain is managed. Ensuring that these changes do not compromise the network's performance or security requires careful planning and extensive testing.

Compatibility with Current Systems

Another consideration is the compatibility of account abstr. with the vast ecosystem of existing blockchain applications and services. Wallets, exchanges, and other services have been built around the traditional account model. Transitioning to an acc. abstraction model will require these services to update their infrastructure, which may be a complex and resource-intensive process. Furthermore, there is a need for standardization across the industry to ensure that different implementations of account abstr. can work seamlessly together.


Acc. abstraction represents a significant leap forward in the quest for a more user-friendly blockchain experience. By streamlining the transaction process and offering enhanced security features, acc abstraction has the potential to make blockchain technology more accessible to a broader audience. However, the path to widespread adoption is not without its obstacles. Technical challenges and compatibility issues must be carefully navigated to integrate it into the existing blockchain landscape.

Key Takeaways

How to Add Gnosis Chain to MetaMask: A Simple Tutorial


03 Nov 2023
How to Add Gnosis Chain to MetaMask: A Simple Tutorial

As the cryptocurrency ecosystem expands, there is an increasing need for various blockchains with distinct capabilities. Gnosis Chain enters the scene, offering a selection of unique characteristics. By integrating Gnosis Chain with MetaMask, users can access a more comprehensive array of decentralized services. We will walk you through the steps to add Gnosis Chain to your MetaMask wallet in this tutorial.


Setting up MetaMask

Before exploring the integration of Gnosis Chain, it is crucial to have MetaMask installed and operational:

  • Download and Install: If you have not done so already, visit the official website to download and install the MetaMask browser extension.
  • Setup Account: After completing the installation, create your account and make sure to remember the provided seed phrase. This phrase serves as your primary means for account recovery, so keep it secure.
  • Secure Your Account: Protecting your MetaMask account is of utmost importance. Use a robust password and never disclose your seed phrase to anyone.

Gnosis Chain

It is always helpful to have a basic understanding before incorporating any new blockchain into your wallet:

  • Gnosis Chain Overview: Gnosis Chain, a rising star in the blockchain world, brings a range of decentralized solutions to the table, such as prediction markets and decentralized trading platforms.
  • Benefits & Features: Among Gnosis Chain's main selling points are its accelerated transaction speeds and potentially lower fees when compared to congested networks.

Tutorial: How to Add Gnosis Chain to MetaMask

In the top right-hand corner of your browser, you'll find the wallet. If pinned, click on the MetaMask fox icon; if not, click the three dots in the top-right corner. The following screen will appear:

An option to expand the wallet to a new browser page is available by clicking "Expand view:"

This action will launch MetaMask in a new tab:

By clicking on the ‘Ethereum mainnet’ in the top left corner, you can add another network. Click ‘Add Network’

Choose option ‘Add a network manually’

Then, input the information below:

Network Name: Gnosis Chain formerly xDai


ChainID: 100

Symbol: XDAI

Block Explorer URL:

After saving the settings, Gnosis Chain will be added to your network.

The Benefits of Adding Gnosis Chain to MetaMask

With multiple blockchains becoming more common, integrating Gnosis Chain with MetaMask offers numerous advantages:

Expanded Capabilities: Accessing Gnosis Chain through MetaMask opens up a collection of exclusive applications and features inherent to this particular blockchain, which may include unique dapps or cutting-edge financial products.

Diversification: The crypto domain is extensive and constantly growing. By incorporating various chains like Gnosis into MetaMask, you broaden your potential investment opportunities and decentralized application experiences, ensuring no opportunities are missed.

Speed & Cost-Effectiveness: Network congestion and high gas fees on established platforms like Ethereum can discourage many users. Gnosis Chain's architecture has the potential to provide relief through quicker transaction times and more affordable fees.

In summary, as the possibilities within the crypto sphere continue to evolve, tools like MetaMask grant users access to this expanding world. By adding chains like Gnosis, users can stay ahead in this decentralized revolution.


By bridging platforms like Gnosis Chain with accessible tools like MetaMask, individuals not only amplify their engagement with decentralized applications but also fortify their position in this expansive realm. The integration of Gnosis Chain to MetaMask epitomizes the evolution of the crypto landscape – a testament to its ever-growing diversity and potential. As we continue to delve deeper into the decentralized future, tools and integrations like these will undoubtedly play a pivotal role in shaping our digital experiences and opportunities. Whether you're seeking more efficient transactions, diverse dapp interactions, or simply a broader understanding of the crypto ecosystem, this guide's steps open doors to a new horizon.