ERC-451 · SEMI-FUNGIBLE
one whole token,
one NFT.
NOVA is an implementation of the ERC-451 standard — a rebuild of ERC-404 with the critical bugs fixed. Liquid like an ERC-20, collectible like an ERC-721, and finally deployable at scale.
PREVIEW
a thousand tiny worlds.
WHAT WE FIXED
six things ERC-404 got wrong.
O(Δ) transfers
Mint/burn only the NFT delta on transfer. No iteration over total balance — 55-65% gas reduction vs ERC-404.
Single-write ownership
Owner and owned-index packed in one storage slot. One SSTORE per ownership change.
Recyclable IDs
Burned token IDs land on a stack and get reused on the next mint. ID space stays compact.
Reentrancy-safe
ERC-20 and ERC-721 entrypoints are guarded. safeTransferFrom respects ERC-721 receivers.
Bounded exemption
Toggling an exemption walks the holder's own NFT list, never the global supply. No block-gas blowups.
Correct ERC-165
Reports ERC-20 + ERC-721 + ERC-721 Metadata accurately. Marketplaces and indexers don't choke.
THE STANDARD
ERC-451, in one paragraph.
A single contract exposes both the ERC-20 and ERC-721 interfaces. The fungible balance and the NFT inventory are linked by a fixed conversion: 1 whole unit (1e18) = 1 NFT. Transfers mint or burn NFTs to cover the delta between the sender's and receiver's whole-balance counts — never the full holdings. Exempt addresses (AMM pools, bridges) skip the NFT side entirely. Burned IDs are kept on a stack and reused, so the live ID space matches the live supply.