👉 This EIP extends the NFT metadata JSON schema defined in EIP-721 and EIP-1155, adding a `dStorage` key that provides information about how the NFT data is stored.
👉 As highly valuable crypto properties, NFT assets intrinsically demand guaranteed storage to assure their **immutability**, **reliability**, and **durability**. NFT ownership is tracked by [EIP-721](./eip-721.md) or [EIP-1155](./eip-1155.md) smart contracts, hence persisted in blockchain, which is not a problem. But how about the mime-type assets that NFT tokens represent? Ideally, they should also be stored in some reliable and verifiable decentralized storage system that is designed to store larger amounts of data than the blockchain itself. As an effort to promote **decentralized storage** adoption in NFT world, we propose to add additional **dStorage** information into NFT metadata JSON schema.
👉 As a refresher, let’s review existing NFT metadata JSON schema standards. [EIP-721](./eip-721.md) defines a standard contract method `tokenURI` to return a given NFT’s metadata JSON file, conforming to the *[EIP-721](./eip-721.md) Metadata JSON Schema*, which defines three properties: `name`, `description` and `image`.
👉 Similarly, [EIP-1155](./eip-1155.md) also defines a standard contract method `uri` to return NFT metadata JSON files conforming to the *[EIP-1155](./eip-1155.md) Metadata JSON Schema*, which defines properties like `name`, `decimals`, `description`, `image`, `properties`, `localization`, etc.
👉 Besides, as the world’s largest NFT marketplace nowadays, OpenSea defines their own *Metadata Standards*, including a few more properties like `image_data`, `external_url`, `attributes`, `background_color`, `animation_url`, `youtube_url`, etc. This standard is de facto respected and followed by other NFT marketplaces like LooksRare.