NFT Marketplace Royalty Standards (EIP-2981) 3

Question 1

A contract wants a flat 5% royalty on all tokens. How should royaltyInfo compute the amount?

Accepted Answer

Return salePrice * 500 / 10000

Answer

Using basis points, 5% equals 500/10000 of the salePrice.

Question 2

What is a common pattern for storing the royalty receiver in an EIP-2981 implementation?

Accepted Answer

A settable address variable, often the creator or a payout splitter

Answer

Implementations store a configurable receiver, frequently a creator wallet or a revenue-splitting contract.

Question 3

OpenZeppelin's ERC2981 implementation lets you set royalties at which levels?

Accepted Answer

A default for the collection and per-token overrides

Answer

OpenZeppelin provides _setDefaultRoyalty and _setTokenRoyalty for collection-wide and token-specific values.

Question 4

In OpenZeppelin's implementation, how is the royalty fraction expressed by default?

Accepted Answer

In basis points out of 10000

Answer

The default _feeDenominator returns 10000, so fees are set in basis points.

Question 5

What happens if you call _setTokenRoyalty with a feeNumerator greater than the denominator in OpenZeppelin's ERC2981?

Accepted Answer

It reverts because royalty exceeds sale price

Answer

OpenZeppelin reverts when the numerator exceeds the denominator to prevent royalties larger than the sale price.

NFT Development Practice Test