Product and SKU identity
A productId identifies a particular catalog product. Each product can have multiple SKUs, which carry condition, printing variant, and language. Keep the skuId with every price, history series, or offer that returns one.
Market observations
Market prices are in USD and include source timing. fetchedAt tells you when a section was retrieved; cacheHit tells you when a cached observation was served. A null price means no observation was available.
SKU-LEVEL PRICE
{
"skuId": 123,
"condition": "Near Mint",
"variant": "Holofoil",
"language": "English",
"marketPrice": 5.45,
"calculatedAt": "2026-09-29T12:30:00.000Z"
}