A standard ownership query names one individually tracked token.
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A library’s owner record for inventory item 42 differs from merely counting how many books a member holds.
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Build a transfer call from typed fieldsStep 1 / 4
The standard transfer interface takes an address and a raw integer amount. This diagram uses address one and amount one hundred.
The standard transfer interface takes an address and a raw integer amount. This diagram uses address one and amount one hundred.Keccak-256 of the canonical signature supplies the first four bytes. The transfer selector is a9059cbb.An address is twenty bytes. Standard ABI encoding adds twelve zero bytes on the left to fill one thirty-two-byte word.The integer one hundred is hex 64, left-padded in word one. Selector plus two words produces sixty-eight bytes of standard calldata.
Animated local teaching model. No wallet, RPC or live blockchain data. Some labels and hashes are abbreviated for readability.
OwnerOf identifies the holder
The ERC-721 interface includes ownerOf(tokenId), while balanceOf(owner) counts the owner’s items. One is an identity query; the other is a count. They answer different questions.
Approvals can have different scopes
ERC-721 supports approval for a particular token and operator approval covering an owner’s tokens under the standard’s rules. A wallet prompt should make the scope understandable.
Transfer events need their actual layout
The familiar Transfer(address,address,uint256) signature also appears in ERC-20 contexts, but ERC-721 commonly indexes the token ID too. Matching the signature hash alone does not prove the topic/data layout or asset semantics.
Do not use the wrong decoder
Our event tool intentionally decodes the common ERC-20 Transfer shape. It does not claim to be a universal NFT log decoder. Supply and inspect the correct ABI when working with other standards.
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Does ERC-721 balanceOf(owner) directly name which token IDs the owner holds?
Counting items and enumerating their IDs require different information.