ERC-721
In short: ERC-721 is the Ethereum token standard for NFTs, or non-fungible tokens. Every token created under it has its own unique ID, so no two tokens are…
ERC-721 is the Ethereum token standard for NFTs, or non-fungible tokens. Every token created under it has its own unique ID, so no two tokens are interchangeable, even when they come from the same contract.
Why it matters
The standard gives every NFT a common interface: a way to look up who owns a specific token, to transfer it safely, and to approve a marketplace to move it on the owner's behalf. An optional metadata extension links each token to a description, usually with a name, an image and attributes. Because wallets and marketplaces read the same interface, an NFT from one project can be displayed and traded across many applications. The token records ownership on the blockchain, while the artwork file itself is often stored elsewhere.
Example
An artist publishes a collection of digital artworks through a single ERC-721 contract. Each artwork receives its own token ID, such as 1, 2 or 3. When a collector buys token 3, the contract records the collector's address as its new owner, and anyone can confirm that ownership on a block explorer.