Since collections and tokens have properties that are simple key-value stores, the user can put any data into the collection and token.
And although it's very useful to have a free structure of data it's not convenient to get into a field without any rules.
Thus, we offer two well-known schemas to use on our chains:
- Unique schema
- ERC721Metadata schema
Unique schema is a schema where all links and metadata is stored on-chain. It allows to store data and attributes flexible with separate access settings for every token field.
This allows, for example, to make a live token, where some parts of the token can be securely changed with guarantees from the blockchain that other parts won't be changed.
ERC721Metadata schema is a schema where token data is stored off-chain, in a common way for the Ethereum world, where the chain stores just a link to an off-chain JSON file.
We presume that the off-chain JSON file should follow the ERC721Metadata JSON Schema or its extension Opensea data format.