Product IDs

Here are the different kinds of product IDs in the Content API for Shopping:

Offer ID

An offerId is a string assigned to a product by a merchant. This ID represents an individual product.

offerId is unique to the set of offers in the Merchant Center database, and is usually a numeric sequential number.

offerId can be an internal SKU number that a merchant assigns to the product.

REST ID

A REST ID is the unique identifier for a product assigned by Google.

REST ID is the productId for REST API calls.

REST IDs are aggregates with the format online:en:label:1111111111. The REST ID consists of the following 4 parts, separated by colons:

Channel ("online" or "local")
Content Language (using the 2-letter designation, for example en or fr)
Feed label (might be the two-letter code for the feed's target country, for example US or FR)
Offer ID

You put this together as channel:contentLanguage:feedLabel:offerId, for example, online:en:US:1111111111.

External Seller ID (Marketplaces)

Marketplaces must assign an external_seller_id to offers uploaded to a multi-seller account. This field represents an individual seller.

external_seller_id values are case-sensitive, and must meet the following criteria:

1-50 characters in length
Only alphanumeric ASCII characters, and underscore (_), hyphen (-), period (.), and tilde (~)

This isn't the same as the internal seller_id field.

The following table summarizes some of the IDs that can be associated with a product:

Attribute	Description	Example	Notes
`offerId`	An ID assigned to a product by a merchant.	`1111111111`	String data type, unique identifier for a product's offer.
REST ID	An ID assigned to a product by Google. In the format `channel:contentLanguage:feedLabel:offerId`.	`online:en:label:1111111111`	Full ID including `offerId`.
`productId`	Used to refer to the REST ID in API calls.	`online:en:label:1111111111`	This is the REST ID of a product.
`id`	Same value as REST ID and `productId`.	`online:en:label:1111111111`	Used inside JSON body of a product to refer to its `productId`.
`external_seller_id`	A seller ID chosen by the Marketplace.	`example-Seller1`	Required for multi-seller accounts. Must be 1-50 characters. Case-sensitive. Digits, and special characters _, -, ., and ~ are accepted.