Marketplace Royalty Standards (EIP-2981) Flashcards

A token sells for 2 ETH with a 7.5% EIP-2981 royalty. What royaltyAmount does royaltyInfo return?

Answer: 0.15 ETH

7.5% of 2 ETH is 0.15 ETH.

Why should royaltyInfo be a view (read-only) function?

Answer: Marketplaces query it without modifying state before paying

royaltyInfo is a pure read used to compute the payout, so it changes no state.

When a creator wants royalties paid in the sale currency (e.g., USDC), how does EIP-2981 handle it?

Answer: royaltyAmount is in the same unit as the salePrice the marketplace passes

Because the amount matches the salePrice unit, passing a USDC salePrice yields a USDC-denominated royalty.

To update a collection's default royalty after deployment, the contract must expose what?

Answer: An access-controlled setter calling _setDefaultRoyalty

A permissioned admin function wrapping _setDefaultRoyalty lets the owner change royalties post-deploy.

A security concern when setting the royalty receiver via a public function is what?

Answer: Missing access control could let anyone redirect royalties to themselves

Without onlyOwner-style protection, an attacker could set themselves as the royalty receiver.

EIP-2981 deliberately leaves which decision to the marketplace?

Answer: Whether and how to actually pay the royalty

The standard defines how to query royalties but leaves payment execution to each marketplace.

For an ERC-1155 contract where every token shares one royalty rate, the simplest implementation is to do what?

Answer: Set a default royalty and ignore per-token overrides

A single default royalty applies to all tokens, avoiding per-token storage overhead.