FREE NFT Development On-Chain Royalties (EIP-2981) Questions and Answers

Question 1

A developer is implementing EIP-2981 for an NFT collection. A marketplace needs to determine the royalty payment for a token with `tokenId` 789 that just sold for 10 ETH. Which function signature must the marketplace call on the NFT contract to get this information?

Accepted Answer

royaltyInfo(uint256 _tokenId, uint256 _salePrice) external view returns (address receiver, uint256 royaltyAmount)

Answer

EIP-2981 specifies a single, universal function, `royaltyInfo`, which takes the token ID and the total sale price as inputs. It returns the address that should receive the royalty and the absolute amount of the royalty to be paid.

Question 2

What is the primary limitation of the EIP-2981 on-chain royalty standard?

Accepted Answer

It can only signal royalty information for a single recipient address.

Answer

The EIP-2981 standard, in its base form, only allows the `royaltyInfo` function to return a single `receiver` address. If royalties need to be split among multiple parties, this logic must be handled off-chain or by setting the receiver to a separate splitter contract, which adds complexity.

Question 3

An NFT project implements EIP-2981, setting a 5% royalty. An owner sells one of the project's NFTs on a marketplace that has publicly stated it does not honor EIP-2981. What is the expected outcome for the creator regarding their royalty payment?

Accepted Answer

The creator will not receive a royalty payment because EIP-2981 is a signaling standard and relies on voluntary adoption by marketplaces.

Answer

EIP-2981 is a signaling mechanism, not an enforcement mechanism. The NFT contract advertises the royalty information, but it is entirely up to the marketplace to query this information and honor the payment. If a marketplace chooses not to implement the standard, no royalty will be paid.

Question 4

When a marketplace calls the `royaltyInfo(tokenId, salePrice)` function, what is the expected format of the `royaltyAmount` that is returned?

Accepted Answer

An absolute monetary value in the same denomination as the `salePrice`.

Answer

The `royaltyAmount` returned by the `royaltyInfo` function is an absolute value, not a percentage. It is the marketplace's responsibility to calculate this amount based on the `salePrice`. The standard mandates that the `royaltyAmount` must be in the same currency or unit of exchange as the `salePrice` provided in the function call.

Question 5

Which of the following describes a key design goal of the EIP-2981 standard?

Accepted Answer

To provide a minimal, gas-efficient, and standardized way for contracts to signal royalty information.

Answer

EIP-2981 was intentionally designed to be simple and gas-efficient. Its primary purpose is to create a universal interface for marketplaces to retrieve royalty information directly from the NFT contract, rather than enforcing the payment itself.

NFT Development Practice Test

NFT Development Practice Test

FREE NFT Development On-Chain Royalties (EIP-2981) Questions and Answers