|Yes||String||A unique identifier of the product (e.g. a SKU)|
|No||String||The name of the product|
|No||Array(String)||An array of categories the product belongs to|
|No||Integer||The price of a product in cents|
|No||String||The URL of an image or thumbnail of the product|
|No||String||The URL of the product page on your site|
|No||Integer||The current stock value of the product|
|No||Date String||A string representing the date on which the product expires|
expiration_datefield is stored as a proper datetime and is simply used for audience segmenting and display purposes.
Any additional params will be treated as strings and added to the
metadatafield of the product.