NFT Guide 2 — Questions and Answers
Question 1: Which Ethereum standard is the foundation for non-fungible tokens?
- ERC-20
- ERC-721 (Correct answer)
- ERC-1155
- ERC-777
Correct answer: ERC-721
ERC-721 defines the standard interface for unique, non-fungible tokens.
Question 2: What does the tokenURI function in an ERC-721 contract typically return?
- The owner's wallet address
- A pointer to the token's metadata (Correct answer)
- The total token supply
- The contract's bytecode
Correct answer: A pointer to the token's metadata
tokenURI returns a URI pointing to a JSON file describing the token's metadata.
Question 3: Why do many NFT projects store metadata and images on IPFS instead of a centralized server?
- It is faster than any CDN
- It provides content-addressed, tamper-resistant storage (Correct answer)
- It is required by ERC-721
- It automatically mints tokens
Correct answer: It provides content-addressed, tamper-resistant storage
IPFS uses content hashes so data cannot be silently changed, improving permanence and trust.
Question 4: In a typical NFT mint function, what is commonly enforced to prevent abuse?
- A maximum supply and per-wallet limit (Correct answer)
- A minimum gas price
- A fixed block number
- Mandatory KYC on-chain
Correct answer: A maximum supply and per-wallet limit
Mint functions usually cap total supply and limit how many tokens one wallet can mint.
Question 5: What is the purpose of the _safeMint function in OpenZeppelin's ERC-721 implementation?
- It encrypts token metadata
- It checks the recipient can receive ERC-721 tokens (Correct answer)
- It refunds gas to the minter
- It pauses the contract
Correct answer: It checks the recipient can receive ERC-721 tokens
_safeMint verifies that contract recipients implement onERC721Received to avoid locked tokens.
Question 6: Which royalty standard provides a common interface for marketplaces to query creator royalties?
- ERC-165
- ERC-2981 (Correct answer)
- ERC-20
- ERC-4626
Correct answer: ERC-2981
ERC-2981 standardizes how contracts report royalty amounts and recipients.
Question 7: What does ERC-1155 enable that ERC-721 does not?
- Storing metadata off-chain
- Managing multiple token types in a single contract (Correct answer)
- Setting royalties
- Pausing transfers
Correct answer: Managing multiple token types in a single contract
ERC-1155 is a multi-token standard supporting both fungible and non-fungible tokens in one contract.
NFT Guide 2
Which Ethereum standard is the foundation for non-fungible tokens?