NFT Advanced NFT Mechanics 2

Question 1

In ERC-721, which function is used to safely transfer a token while checking that the recipient contract can handle ERC-721 tokens?

Accepted Answer

safeTransferFrom

Answer

safeTransferFrom verifies the recipient implements onERC721Received before completing the transfer.

Question 2

What does the ERC-2981 standard add to NFT contracts?

Accepted Answer

Royalty payment information

Answer

ERC-2981 provides a standardized way to signal royalty amount and recipient for secondary sales.

Question 3

Which interface must a contract implement to be recognized for capability detection like ERC-721 support?

Accepted Answer

ERC-165

Answer

ERC-165 defines supportsInterface, allowing contracts to advertise which interfaces they implement.

Question 4

In ERC-1155, why is balanceOfBatch more gas-efficient than multiple balanceOf calls?

Accepted Answer

It queries multiple token IDs in one call

Answer

balanceOfBatch returns balances for many id/owner pairs in a single function call, reducing overhead.

Question 5

What is a common purpose of a tokenURI returning an IPFS hash rather than an HTTP URL?

Accepted Answer

Content-addressed immutability

Answer

IPFS hashes are content-addressed, so the metadata cannot change without changing the hash.

NFT Development Practice Test