Product identifiers: *GTIN*, *MPN*, and Brand
Unique product identifiers allow search engines to match queries with exact manufacturer products. Here is how GTINs, MPNs, and Brand attributes operate.
Why unique product identifiers drive shopping visibility#
Unique Product Identifiers (UPIs) define the exact product you are selling in the global marketplace. Microsoft uses GTINs to group multiple sellers of the same item, compare prices, and display merchant reviews.
As detailed in Microsoft Product Identifier Policy, 2026, products with verified GTINs receive up to 40% more impression volume in competitive shopping auctions.
The three core product identifier types#
Microsoft Merchant Center evaluates three standard identifier fields:
- GTIN (Global Trade Item Number): Universal international barcode numbers including UPC (12 digits), EAN (13 digits), and ISBN (for books).
- Brand: The official brand or manufacturer name.
- MPN (Manufacturer Part Number): The manufacturer's alphanumeric part identifier.
The identifier_exists escape hatch#
If you sell custom handmade goods, vintage clothing, or private-label products without barcodes, set identifier_exists=FALSE as specified in Microsoft Shopping Feed Specs, 2026.
Never set identifier_exists=FALSE on standard brand merchandise that possesses an official GTIN; doing so leads to feed suspension.
Diagnosing and resolving GTIN validation errors#
Check the Merchant Center Diagnostics tab for 'Invalid GTIN check digit' or 'Missing required identifier' errors, correcting corrupted SKU barcode strings at the source inventory level.
Consult our Microsoft Ads Hub for feed diagnostics tools.
Product identifier submission decision tree#
The table below guides identifier attribute selection based on product merchandise category.
| Product Category | Brand Field | GTIN Field | MPN Field | identifier_exists |
|---|---|---|---|---|
| New Brand Merchandise | Required | Required (UPC/EAN) | Recommended | TRUE (Default) |
| Custom / Handmade / One-off | Required / Optional | Omit | Omit | FALSE |
| OEM Replacement Parts | Required | Optional | Required (Exact Part #) | TRUE (Default) |
| Published Books | Required (Publisher) | Required (ISBN-13) | Omit | TRUE (Default) |
Frequently asked questions#
What is a GTIN and where do I find it?
A GTIN (Global Trade Item Number) is the barcode number printed on a product's retail packaging, commonly represented as a 12-digit UPC in North America or 13-digit EAN in Europe.
Can I make up a fake GTIN if my product doesn't have one?
No, Microsoft validates GTIN check digits against GS1 international databases; submitting fake GTINs results in immediate feed disapproval.
When should I set identifier_exists to FALSE in my feed?
Set identifier_exists to FALSE only for custom products, handmade goods, vintage apparel, or white-label merchandise that has no official manufacturer barcode.
Does MPN replace GTIN in Microsoft Merchant Center?
For products with assigned GTINs, MPN cannot replace GTIN; both should be submitted together when available for maximum query relevance.
Why are my products disapproved for 'Invalid GTIN'?
This occurs when the barcode string contains invalid characters, incorrect digit lengths (must be 8, 12, 13, or 14 digits), or fails mathematical check digit validation.
Read more on this topic#
The Microsoft Ads Hub
Free tools, campaign guides and live news for every Microsoft Ads format.
Open the hubResponsive search ads and multimedia ads in Microsoft Search
A practical guide to building, pinning, and optimizing Responsive Search Ads and Multimedia Ads on Microsoft Advertising.
Read the entryAd quality and Quality Score components on Bing
A complete breakdown of Microsoft Quality Score components, auction cost impacts, and recovery protocols.
Read the entryPerformance Max asset groups and audience signals
How to structure themed asset groups and attach high-impact audience signals in Microsoft Performance Max.
Read the entryStruggling with Merchant Center product disapprovals?
folkfox audits and repairs product identifier schemas to restore full catalog eligibility on Microsoft Shopping.