Glossary
ERC-4906 (NFT Metadata Update)
An Ethereum standard for NFT contracts to signal that token metadata has changed — emits MetadataUpdate / BatchMetadataUpdate events that marketplaces and indexers read.
Before ERC-4906, NFT metadata updates (an attribute changing, a
reveal happening, image upgrades) had no on-chain signal —
marketplaces and indexers had to poll or guess when to re-fetch.
ERC-4906 adds two events: MetadataUpdate(tokenId) and
BatchMetadataUpdate(fromTokenId, toTokenId).
The standard activates instantly with no contract upgrade if emitted from a compatible contract. OpenSea, Reservoir, and most modern NFT indexers read these events to refresh metadata automatically. Dynamic NFTs and reveal mechanics rely on it.