What is ERC-721?

ERC-721 is the widely adopted standard for NFTs on Ethereum and compatible chains. It specifies how a token can be unique and individually owned, with each token carrying its own identifier. By following this standard, NFTs work consistently across marketplaces and wallets, just as ERC-20 does for interchangeable tokens.

This matters because the standard is what makes NFT badges, collectibles, and passes portable and recognisable across the ecosystem. When you receive a quest badge or a collectible, it is usually an ERC-721 token.

Example: a project mints participation badges as ERC-721 tokens, so any compatible wallet or marketplace can display and verify them individually.

Safety note: because ERC-721 tokens can be minted freely by anyone, receiving one proves nothing about legitimacy, and scam NFTs are commonly airdropped as bait to lure clicks. Interacting with a malicious NFT’s linked site or approving its contract can lead to a drain. Verify collections through official sources, and ignore unsolicited NFTs rather than engaging with them. Related terms include NFT, ERC-20, token approval, and smart contract.