How would I allow the current owner of an NFT to append a fixed number of metadata bytes to their token on chain. Is this something that can be done with ERC-1155 or ERC-721. Or is this a whole new beast?

I would expect the owner would be paying the gas cost to accomplish this append operation. In my usecase there would not be any non technical reason to restrict how often an owner can append these bytes.

What is a rough estimate of the gas cost to perform and store such an append?

1 Answer 1


EIP-721 provides a function tokenURI that returns a JSON schema that can be used to attach extra info. But there are no indications how to modify the schema, how to make changes, or how to signal them.

Similarly EIP-1155 provides a function uri function, it has an explicit properties field in the JSON schema that can be customized and provide events to trigger when there were modifications.

  • Can these functions be called by the current owner? I thought these were only ever called once by the issuer.
    – BitMark
    Mar 17, 2021 at 12:32

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.