Gas cost optimization in 1/n ERC721

[abcoathup]

Hi @bahlsenwitz,

Welcome to the community

@bahlsenwitz

For all the instances of tokens of a particular set (1/n, 2/n, …, n/n), where all the tokens correspond to the same ipfsHash, would it be possible to use the same tokenURI for all of them?

Yes. The OpenZeppelin Contracts ERC721 implementation supports:

• tokenURI
• baseURI + tokenURI
• baseURI + tokenID

OpenZeppelin/openzeppelin-contracts/blob/v3.4.0-rc.0/contracts/token/ERC721/ERC721.sol#L142-L150

If you were using centralized metadata (e.g. from a server) then the lowest cost minting is just setting a single baseURI.

If you are using decentralized metadata (e.g. IPFS) then you could override the tokenURI function (from Release Candidate for Contracts 3.4) to return your IPFS.

@bahlsenwitz

Would this reduce the amount of storage, and correspondingly the amount of gas used when the contract is called?

Using either baseURI + tokenID or a single IPFS hash for the entire contract would reduce the cost of minting as you wouldn't need to store any metadata onchain for each token ID.

@bahlsenwitz

Would this have any negative externalities regarding the correct functionality as its implemented today?

Not that I am aware of. You should test this with any services that you want to use (e.g. OpenSea) and what format you need to use for the URI when using IPFS.