An MPN (Manufacturer Part Number) is the unique code a manufacturer assigns to one of its products, used together with the brand field to identify products that do not have a GTIN.
When a product has no GTIN — or before a GTIN has been issued — Google and most marketplaces accept the combination of brand + MPN as an alternative identifier. The MPN is whatever code the manufacturer uses internally: a model number, a part code, a SKU as long as it is the manufacturer's SKU and not the retailer's.
The format is loose. MPNs can include letters, numbers, dashes, and dots; there is no check digit and no central registry. The only rule is uniqueness within the manufacturer: every retailer selling the same product should be submitting the same MPN under the same brand. When two listings disagree on MPN for the same product, Google treats them as separate items and the listings compete with each other rather than aggregate.
A common pitfall is to put the retailer's own SKU in the MPN field. The retailer's SKU is typically internal and varies between shops — using it as MPN breaks the cross-shop match Google needs to merge listings. FeedArc keeps the manufacturer's MPN in a dedicated field and the retailer's SKU in the id field, where it belongs.
A Global Trade Item Number (GTIN) is the international barcode identifier — UPC, EAN, JAN, or ISBN — that uniquely identifies a manufactured product worldwide, issued by GS1.
Google Merchant Center (GMC) is the Google platform where you upload, validate, and manage product feeds that power Google Shopping ads, free listings, Performance Max, and Demand Gen campaigns.
Feed validation is the process of checking a product feed against a channel's schema and rules — required fields, data types, value formats, and business logic — before upload, so errors are caught locally rather than after disapproval.
FeedArc handles manufacturer part number — and 31 other feed concerns — automatically. Free to start, no credit card needed.
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