Content Addressing in Practice

Location-based URLs identify where to fetch data. Content addresses identify what the data is. Hash the bytes, publish the digest, and any peer holding matching content can satisfy the request — integrity is built into the identifier itself.

ERC-721 tokenURI typically returns ipfs://Qm… or ipfs://bafy…. Marketplaces and wallets resolve through gateways, then check that downloaded bytes match the expected CID when possible. Mismatches indicate gateway tampering or a misconfigured upload pipeline.

Dynamic NFTs and upgradeable metadata use patterns like base URI plus per-token ID paths, on-chain SVG, or explicit version fields in JSON. Each approach trades gas cost, transparency, and user trust differently. Document which fields are immutable so buyers know what can change after mint.