ERC-721 Metadata JSON Schema
Every NFT's display (image, name, description, traits) is driven by this metadata schema. Off-chain storage of this JSON (IPFS, Arweave, HTTP) is a critical design decision.
What It Defines
Defines the optional metadata JSON schema for ERC-721 NFTs: name, description, image (URI). The off-chain JSON file pointed to by tokenURI(). Used by OpenSea, marketplaces, and wallets to display NFT art and attributes.
Canonical (Normative)
Convenient (Practical)
The Ethereum community's open process for proposing changes to the protocol. EIPs cover core protocol changes; ERCs (Ethereum Request for Comments) cover application-layer standards like token interfaces.
Related Specs
NFTs, digital ownership, gaming assets, and on-chain certificates all use ERC-721. The standard that launched the NFT market.
JSON is the lingua franca of web APIs. RFC 8259 is short and worth reading once — it clarifies edge cases around numbers, encoding, and trailing commas.