Glossary
ERC-404
A 2024 hybrid token standard that pairs an ERC-20 supply with ERC-721 IDs — burning fractions of a token can mint/burn associated NFTs, blurring fungible and non-fungible.
ERC-404 was introduced in February 2024 by the Pandora project. Each whole token has both an ERC-20 balance and a corresponding ERC-721 ID; sending a fractional amount automatically burns the NFT and re-issues it to a different holder when fractions are re-aggregated.
The standard is not an official ERC (it never went through the EIP process) and has known gas-cost and complexity issues, but it triggered significant interest in hybrid fungible/non-fungible token designs. Several improved variants (DN-404, ERC-7572) have followed.