What is ERC-721?
- Author
- CRYPTO PORT Editorial
- Published
- Updated
- Reading time
- 4 min
In short
ERC-721 is the Ethereum standard for tokens that are individually distinct — NFTs. Each carries a unique ID whose owner is tracked on-chain. What the standard guarantees is the ownership record, not any copyright in the underlying work.
Key points
- A standard for tokens with unique per-item IDs
- Transfers of ownership are recorded on-chain
- The image itself usually lives off-chain
- Owning the token is not the same as owning the rights
Definition
An Ethereum interface standard for non-fungible tokens, where each item is individually identifiable.
Where ERC-20 tracks quantities, ERC-721 tracks which ID belongs to whom. Within one collection, item #1 and item #2 are separate things with separate owners. It is used for membership passes, tickets and proofs of ownership for digital art.
Where the actual file lives matters. On-chain storage is expensive, so contracts usually record only a URL, with the image or audio hosted externally or on IPFS. If that host disappears, the token survives but there is nothing left to display.
Holding the token is also not the same as holding copyright. What you may do with the work depends on the licence the issuer publishes — worth reading before buying, because projects set very different terms.
Watch out for
- · If the artwork sits on a project's own server, it can vanish when the project stops
- · Thinly traded NFTs may simply have no buyer when you want to sell
- · Ownership of the token does not by default include copyright or commercial rights