Practice Test GeeksNFT Development Practice Test
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Guide Flashcards

7 cards from real NFT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

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  1. Which interface detection standard lets contracts advertise that they support ERC-721?

    Answer: ERC-165

    ERC-165 provides supportsInterface, which contracts use to declare ERC-721 compliance.

  2. What is a common reason to use a Merkle tree in an NFT mint contract?

    Answer: To gate an allowlist efficiently on-chain

    A Merkle root lets the contract verify allowlist membership without storing every address.

  3. Why is using block.timestamp or blockhash for NFT trait randomness considered insecure?

    Answer: Miners or validators can influence or predict it

    On-chain values like blockhash are predictable or manipulable, so a service like Chainlink VRF is preferred.

  4. What does 'lazy minting' refer to in NFT development?

    Answer: Deferring the on-chain mint and gas cost until the first sale

    Lazy minting creates the token on-chain only when it is purchased, shifting gas costs to the buyer.

  5. In the ERC-721 metadata JSON, which field conventionally holds the displayed picture link?

    Answer: image

    The metadata standard uses an 'image' field containing a URL to the asset.

  6. What is the benefit of making baseURI updatable but then renouncing or freezing it?

    Answer: It allows a reveal then guarantees metadata permanence

    A mutable baseURI supports a delayed reveal, and freezing it afterward assures collectors metadata won't change.

  7. Which function must be called to let a marketplace transfer your NFT on your behalf?

    Answer: approve or setApprovalForAll

    approve grants per-token access while setApprovalForAll grants collection-wide access to an operator.