Hashtag Web3 Logo

NFTs: Digital Ownership

9 min
beginner

Beyond the hype

NFTs got famous for $69 million art sales and cartoon apes. Behind the hype, the technology is simple and useful: NFTs let you prove you own a unique digital item on a blockchain.

An NFT is a token with a unique ID. Unlike USDC (where every token is the same), each NFT is one-of-a-kind. The blockchain records who owns it, who created it, and its entire transaction history.

How NFTs work technically

An NFT is just a number (token ID) stored in a smart contract, linked to a wallet address.

NFT Smart Contract (ERC-721) Token ID Owner Metadata URI #1 0xA1b2...c3d4 ipfs://Qm...abc #2 0xE5f6...g7h8 ipfs://Qm...def #3 0xI9j0...k1l2 ipfs://Qm...ghi

The smart contract is a table. Each row has a token ID, an owner address, and a link (URI) to metadata. The metadata (stored off-chain, usually on IPFS) contains the name, description, and image URL.

When you "buy" an NFT, the smart contract changes the owner field from the seller's address to yours. The blockchain records this permanently.

Use cases beyond art

Use caseHow NFTs helpExamples
Art and collectiblesProvable ownership and royaltiesFoundation, SuperRare
Event ticketsCannot be counterfeited, easy to transferGET Protocol
Domain namesOwn a .eth name as an NFTEthereum Name Service (ENS)
Game itemsTrade items across games and marketsGods Unchained, Axie Infinity
Membership passesToken-gate access to communitiesBored Ape Yacht Club
Real-world assetsRepresent ownership of physical itemsReal estate tokens, luxury goods

The ERC-1155 standard

ERC-721 creates one token per item. ERC-1155 allows a single contract to manage both fungible and non-fungible tokens. A game studio can use one ERC-1155 contract for both unique swords (non-fungible, each is different) and gold coins (fungible, all identical).

Key takeaways

  • NFTs are tokens with unique IDs that prove ownership of a specific item.
  • ERC-721 is the standard for unique tokens; ERC-1155 supports both unique and identical tokens.
  • Images and metadata are usually stored off-chain (IPFS), not on the blockchain itself.
  • Real use cases extend beyond art: tickets, domains, game items, memberships.

Quiz: NFTs: Digital Ownership

1 / 5

What makes an NFT 'non-fungible'?