Guide to ERC-721, ERC-721A, and ERC-721C tokens

ERC standards provide a blueprint for creating tokens on the Ethereum blockchain and one of the earliest blueprints was ERC 20. All tokens on the blockchain were primarily ERC-20 tokens, which were fungible tokens until ERC 721 was introduced. Fungible means that all tokens were identical in value to every other token in a given collection and thus, interchangeable. In this article, we’ll understand how ERC 721 emerged with the concept of non-fungibility and the later advancements like ERC-721 & ERC-721C to this base model.

ERC-721

ERC-721 was proposed in January 2018 for non-fungible tokens, i.e. NFTs. Unlike fungible tokens such as Bitcoin or Ethereum where each token is identical to the other, each NFT is unique. This uniqueness makes them perfect for representing ownership of unique assets like collectible items, access keys, lottery tickets, numbered seats for concerts, etc.

With ERC 721, you can

• trade NFTs with other accounts and for other token types like cryptocurrencies
• limit who can transfer NFTs
• pause token transfers

• determine the total supply of NFTs on a network

• know the owners of a specific asset
• burn the assets

There have been a number of popular NFT projects in the past few years including CryptoKitties and CryptoPunks.

ERC-721A

ERC-721A is an improved version of ERC-721 that increases gas efficiency through batch minting. This standard was proposed by the Azuki team in. This means it allows developers to mint multiple NFTs simultaneously at the same gas price. This standard is ideal for generative art NFT projects where there are thousands of NFTs to be minted. It can also be used during the busy mint phases of any project.

Some popular examples of ERC 721A have been the Adidas airdrop, Moonbirds, Doodles Dooplicator, etc.

ERC-721C

The ERC721-C is a new standard developed by a blockchain gaming company called Limit Break that allows creators to enforce royalties on-chain. In simpler terms, it means that artists and developers can now set rules for how they earn from their creations directly on the blockchain. They can decide where their NFTs are sold and choose which contracts or applications can interact with their NFTs.

Basically, it allows royalties to be programmable which means that creators can prevent their works from being traded on platforms that don’t pay them royalties.

So, if a platform doesn’t charge fees and therefore doesn’t pay royalties to the creators, the creators can simply choose not to allow their NFTs to be traded there. This gives more power and control to the creators over their works.

The possibilities that these standards have unlocked are immense. ERC 721 introduced the concept of no-fungibility which then led to the creation of over $38.2 billion worth of market. Then adding to its functionalities, ERC 721A brings down the gas fees by allowing creators to mint thousands of NFTs for the price of just one while ERC 721C gives creators more control over their artwork and the royalties attached to it.