Introduces a new standard for storing arbitrary metadata directly onchain for ERC-721, ERC-1155, ERC-6909, and ERC-8004 registries.
Key features:
Key-value pair interface: string keys mapped to bytes values for each token
Required getMetadata() function and MetadataSet event
Backwards compatible with existing token standards
Enables trustless AI agents, proof of personhood, and custom metadata
This addresses the long-felt need for uniform onchain metadata storage while avoiding gas inefficiencies.
Note on Standard History:
This onchain metadata standard was originally introduced as part of ERC-8041 on September 30, 2025 (commit 13f11f2). ERC-8041 later pivoted to focus on fixed-supply agent collections, so this core metadata functionality is being reintroduced as a standalone standard.