What EIP-2981 Is
EIP-2981 is an Ethereum Improvement Proposal that defines a standard interface for NFT royalty information. Any ERC-721 or ERC-1155 contract that implements EIP-2981 exposes a `royaltyInfo(tokenId, salePrice)` function that returns the royalty recipient address and the royalty amount owed. Any marketplace that queries this function before processing a secondary sale can calculate and distribute the royalty automatically. The limitation: EIP-2981 is not enforced by the token contract — it is a convention that marketplaces choose to honor. A marketplace can query `royaltyInfo()`, note the royalty amount, and choose not to pay it.
Technical Implementation
// OpenZeppelin ERC2981 implementation
import "@openzeppelin/contracts/token/common/ERC2981.sol";
contract MyNFT is ERC721, ERC2981 {
constructor() ERC721("MyNFT", "MNFT") {
// Set 5% royalty to creator on all tokens
_setDefaultRoyalty(msg.sender, 500); // 500 = 5% (out of 10000)
}
}Royalty Enforcement Models
Marketplace-Enforced (Current Status Quo)
Marketplaces voluntarily enforce royalties. OpenSea currently enforces creator royalties on collections that use their on-chain enforcement tool. Blur enforces royalties on collections that block Blur's fee-free trading. This creates a fragmented landscape where enforcement depends on which marketplace a trade occurs on.
On-Chain Enforcement (Transfer Restriction)
The NFT contract only allows transfers to approved marketplace contracts — marketplaces that have agreed to collect and pay royalties. Trade-off: Reduces composability. NFTs cannot be used in DeFi protocols, collateralized for loans, or transferred to cold storage without going through an approved marketplace.
The Blur Effect and Its Aftermath
In late 2022, Blur launched with a zero-fee, optional royalty model. Sellers could choose not to pay royalties. OpenSea responded by removing royalty enforcement for collections already trading on platforms that did not enforce royalties. This significantly reduced creator royalty income across the ecosystem. The lesson for new collections: If royalty income is material to your project's financial model, do not rely on marketplace voluntary enforcement. Either build your own marketplace, deploy on a platform with contractual enforcement commitments, or accept that royalty enforcement is a best-effort social contract.
