Token Standards (ERC-721/1155) Flashcards
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Read the first 7 Token Standards (ERC-721/1155) flashcards as text
A contract calls safeTransferFrom to a recipient contract that returns the wrong magic value. What happens?
Answer: The transfer reverts
If onERC721Received/onERC1155Received doesn't return the expected selector, the transfer reverts.
Which is true about ERC-1155 semi-fungible tokens?
Answer: An id can have a supply greater than 1 yet still be treated as a distinct type
A semi-fungible id holds multiple identical units, like event tickets, under one id.
What is a common reason to store ERC-721 metadata on IPFS instead of a centralized server?
Answer: Content immutability and decentralized availability
IPFS content addressing makes metadata tamper-evident and not reliant on one server.
In ERC-721, calling ownerOf on a nonexistent tokenId typically does what?
Answer: Reverts
Standard implementations revert when querying ownerOf for a token that doesn't exist.
Which design lets ERC-1155 reduce deployment cost for many game items?
Answer: One contract managing many token ids
A single ERC-1155 contract manages unlimited token ids, avoiding per-item deployments.
What does getApproved(tokenId) return in ERC-721?
Answer: The single approved address for that token, or zero
getApproved returns the lone address approved to transfer that token, or address(0) if none.
When integrating ERC-2981 royalties, where is the royalty actually enforced?
Answer: By marketplaces voluntarily honoring royaltyInfo
ERC-2981 only signals royalties; marketplaces must choose to pay them, as it isn't enforced on-chain.