Finst

ERC-721

ERC-721 is a technical standard on Ethereum for unique tokens. This standard is often used for NFTs.

Last updated • 2 min read
Get more Finst news in your feed

What is ERC-721?

An ERC-721 token has its own number, called the tokenId. A smart contract keeps track of which blockchain address owns that specific token.

Think of them as numbered tickets. Ticket 14 and ticket 15 might be for the same event, but they’re two different tickets. In the same way, each ERC-721 token can be identified individually.

The smart contract’s address and the tokenId together form the technical identity of a single token. Because they follow shared rules, crypto wallets and apps can recognize and send these NFTs.

An example of ERC-721

Suppose you have an NFT with tokenId 42. The ERC-721 contract records your address as its owner.

If you send this NFT to someone else, the contract changes the recorded owner of tokenId 42. The token stays the same; only the owner’s address changes.

Why is ERC-721 important in crypto?

ERC-721 is a widely used foundation for NFTs, such as digital art, collectibles, game items, and tickets. The standard lets different apps work with these tokens in similar ways.

That’s why ERC-721 may be mentioned as a technical standard in news about NFT projects. It mainly tells you how the token is recognized, who owns it, and how it can be sent. It doesn’t automatically tell you anything about a project’s value or reliability.

A unique tokenId also doesn’t automatically prove that an image, artwork, or physical object is unique or authentic. Owning an NFT also doesn’t automatically give you the copyright or legal ownership of the content it’s linked to. Pay close attention to permissions, too: with approval for all tokens, another address can move all your ERC-721 tokens.

Disclaimer: This content is for informational purposes only and does not constitute financial, investment, legal, or tax advice. The information provided may be incomplete, inaccurate, or outdated and should not be relied upon as such. Nothing on this website should be considered a recommendation to buy, sell, or hold any cryptocurrency. Investing in crypto-assets involves risk of loss.