A token numbered 42 is not a complete NFT identifier. Many different contracts can use that number, and a displayed image can be shared across unrelated listings. ERC-721 supplies a precise framework for identifying a token and querying its recorded owner, while keeping optional metadata distinct from the core ownership interface.
Follow the evidence
Trace how the event could reach markets, then inspect a competing explanation.
Compare explanations
Switch lenses to see what each account explains—and what remains uncertain.
Consider hypothetical Contract A and Contract B, each containing token 42 on the same network. The numbers match, but the contract addresses differ, so these are different tokens. A screenshot showing only the number cannot establish which asset an offer concerns. A matching collection title is also insufficient for that identification. Now imagine that Contract A’s token refers to an externally hosted image. Viewing the image helps explain what the listing displays, but that view does not independently verify the contract or the current ownership record. Nor does the mere presence of an image field establish who controls its hosting, whether it can change or how long it will remain available. The same separation matters when a listing mentions usage rights. A protocol ownership response is a software record. To understand any associated permission to reproduce or commercially use an image, a reviewer needs the relevant terms and evidence linking them to the asset. Those rights cannot be read directly from the token number or an owner address alone.
Consider hypothetical Contract A and Contract B, each containing token 42 on the same network. The numbers match, but the contract addresses differ, so these are different tokens. A screenshot showing only the number cannot establish which asset an offer concerns. A matching collection title is also insufficient for that identification. Now imagine that Contract A’s token refers to an externally hosted image. Viewing the image helps explain what the listing displays, but that view does not independently verify the contract or the current ownership record. Nor does the mere presence of an image field establish who controls its hosting, whether it can change or how long it will remain available. The same separation matters when a listing mentions usage rights. A protocol ownership response is a software record. To understand any associated permission to reproduce or commercially use an image, a reviewer needs the relevant terms and evidence linking them to the asset. Those rights cannot be read directly from the token number or an owner address alone.
Record the network, exact contract address and token ID together. If checking current ownership, document the chain state or observation time and the method used to query the contract. Separately preserve the metadata URI, retrieved content and applicable issuer terms when those materials matter to the proposed use. For a marketplace comparison, trace the displayed listing back to the identified contract rather than relying on its thumbnail. Explain any missing evidence directly: an unavailable metadata resource, for example, leaves a different uncertainty from an unresolved contract identity. This makes the review useful without implying that a visual match authenticates the asset. The ERC-721 specification, reviewed on 8 October 2026, establishes the interface discussed here. The contract names and token number in the examples are invented. No particular collection, ownership dispute or set of legal rights has been assessed.
The standard separates the identifier and the interface
EIP 721 specifies a unique unsigned 256-bit token identifier within each ERC-721 contract. The combination of contract address and token ID identifies a token within the relevant Ethereum chain. The ownerOf interface returns the address recorded as owner for a valid token ID. Ethereum Improvement Proposal 721 — Non-Fungible Token Standard
The specification describes metadata as an optional extension. Its tokenURI interface can provide a URI for information about the represented asset, with a suggested JSON structure that includes fields such as name, description and image. The core token identity and the linked descriptive material are different layers. Ethereum Improvement Proposal 721 — Non-Fungible Token Standard
Two matching numbers can represent different tokens
Consider hypothetical Contract A and Contract B, each containing token 42 on the same network. The numbers match, but the contract addresses differ, so these are different tokens. A screenshot showing only the number cannot establish which asset an offer concerns. A matching collection title is also insufficient for that identification.
Now imagine that Contract A’s token refers to an externally hosted image. Viewing the image helps explain what the listing displays, but that view does not independently verify the contract or the current ownership record. Nor does the mere presence of an image field establish who controls its hosting, whether it can change or how long it will remain available.
The same separation matters when a listing mentions usage rights. A protocol ownership response is a software record. To understand any associated permission to reproduce or commercially use an image, a reviewer needs the relevant terms and evidence linking them to the asset. Those rights cannot be read directly from the token number or an owner address alone.
Keep an asset record that can be checked
Record the network, exact contract address and token ID together. If checking current ownership, document the chain state or observation time and the method used to query the contract. Separately preserve the metadata URI, retrieved content and applicable issuer terms when those materials matter to the proposed use.
For a marketplace comparison, trace the displayed listing back to the identified contract rather than relying on its thumbnail. Explain any missing evidence directly: an unavailable metadata resource, for example, leaves a different uncertainty from an unresolved contract identity. This makes the review useful without implying that a visual match authenticates the asset.
The ERC-721 specification, reviewed on 8 October 2026, establishes the interface discussed here. The contract names and token number in the examples are invented. No particular collection, ownership dispute or set of legal rights has been assessed.