🚸NFT Standards

Despite abnormally high transaction fees, at present Ethereum still dominates the NFT space: according to Etherscan.io, there are over 7500 NFT smart contracts deployed with a daily number of transactions going over 7000, the number of minted tokens being over a million and the number of holders being in the billions unique owner addresses.

The most popular NFT standards in Ethereum space are currently ERC-721, and ERC-1155. Nonetheless, the other blockchains are also have hosted few NFT projects like Bitcoin provides Counterparty protocol.

EOS released the recommended standard for NFT smart contracts, which is similar to ERC-721.

The Interchain NFT and Metadata Standardization conducted extensive research of NFT tokens and their Metadata standards.

Nerv aims to comply with this interchain standard and deliver the network protocol that is applicable to and will be able to describe a wide range of NFT formats known in order to prewire the NFT interoperability for most if not all known NFT standards, which is explained in detail further.

ERC-721

ERC-721 is the most popular NFT standard that serves as a base for many standards inheriting its properties. It provides capability to mint, burn, and transfer tokens. The methods such as allow and transferFrom enable withdrawing tokens on the owner’s behalf. It is also possible to include random data in the transfer transactions and perform safe transfers that verify that the receiving party (a smart contract) is capable of receiving the NFT token and can handle it by executing a onERC721Received call-back method.

All these features are or will be covered by the basic functionality of NFT Module, which is in the core of Nerv. Also, the ERC-721 standard describes the ERC721Metadata metadata standard, which includes collection name, token symbol, and token URI. Collection name, description and symbol (token prefix) are the properties of any Unique collection, and token URI can be set as a part of the Off-chain schema. Token supply as well as BalaceOf parameters also translate one to one to Unique collection parameters: number of created tokens and balance.

ERC-1633 Refungible standard covered in architecture overview.

ERC-1155

The ERC-1155 standard mainly adds batch operations on top of ERC-721. This functionality is not directly changing the data formats for NFT, but is a convenient way to automate and optimize operations on multiple NFTs. Also, even though the batch minting is not explicitly included in ERC-1155, Nerv implements this feature as well, and will implement batch transfer operations.

ERC-994 and ERC-998

Delegated NFT and Composable NFT add the relationship layer, e.g. “NFTs are arranged in a federated, tree-like format”. In order to stay efficient while accommodating this functionality, Nerv Blockchain will add a pallet that will allow to create directed labeled interconnections between NFTs.

ERC-809 and ERC-1201

Ownership is a capacious term, which serves as an umbrella for many rights that authorize entities for many different actions. Due to this reason, it is important to create the framework capable of providing granular definitions and enforcements for these authorizations. Renting of NFT described in standards ERC-809 and ERC-1201 are only a small subset of such authorizations.

Nerv Metadata Schemas

Standardization is important in order to set the grounds for interoperability between multiple chains, but also is flexibility. We set the goal to support many standards to stay interoperable and at the same time flexible enough to accommodate new schema standards as they appear. Thus, the Network does not restrict the schema to any format, but allows to select the format out of existing known standards to the moment ex. ERC-721. Lil wallets will be able to read the schema version that is stored on-chain and display the NFTs appropriately.