The primary object in the OpenSea API is the asset, which represents a unique digital item whose ownership is managed by the blockchain. The below CryptoSaga hero is an example of an asset shown on OpenSea.

Here's an overview of some of the fields contained in an asset:

Field Name	Description
`token_id`	The token ID of the NFT
`image_url`	An image for the item. Note that this is the cached URL we store on our end. The original image url is `image_original_url`
`background_color`	The background color to be displayed with the item
`name`	Name of the item
`external_link`	External link to the original website for the item
`asset_contract`	Dictionary of data on the contract itself (see asset contract section)
`owner`	Dictionary of data on the owner (see account section)
`traits`	A list of traits associated with the item (see traits section)
`last_sale`	When this item was last sold (null if there was no last sale)

Traits

Traits are special properties on the item, that can either be numbers or strings. Below is an example of how OpenSea displays the traits for a specific item.

Here are some of the fields contained in a trait:

Field Name	Description
`trait_type`	The name of the trait (for example color)
`value`	The value of this trait (can be a string or number)
`display_type`	How this trait will be displayed (options are `number`, `boost_percentage`, `boost_number`, and `date`). See the adding metadata section for more details

Asset contracts

Asset contracts contain data about the contract itself, such as the CryptoKitties contract or the CoolCats contract. Here are the field associated with an asset contract:

Field Name	Description
`address`	Address of the asset contract
`name`	Name of the asset contract
`symbol`	Symbol, such as CKITTY
`image_url`	Image associated with the asset contract
`description`	Description of the asset contract
`external_link`	Link to the original website for this contract