Intermediate

NFT (ERC-721)

Intermediate Track 02
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Why is a JPEG worth millions?

Beeple's 'Everydays' sold at Christie's for $69.3 million.
NFTs are digital proof of ownership โ€” anyone can copy but no one can forge ownership.

What you'll learn in this module

  • โ†’ ERC-721's unique tokenId and the ownerOfยทtransferFrom interface
  • โ†’ NFT metadata structure via tokenURI and IPFS
  • โ†’ Real NFT cases BAYCยทCryptoPunksยทENS and comparison with ERC-1155
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Unique tokenId

Each NFT is identified by a uint256 tokenId in the contract. No two are the same.

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Ownership record

Query current owner with ownerOf(tokenId). All transfer history on the blockchain.

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Metadata

tokenURI โ†’ JSON on IPFS/Arweave. Stores images, attributes, and descriptions.