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Merchant Center issue

Fix limited performance due to missing identifiers

This is the most common identifier warning in Google Merchant Center. Google now shows it as "Missing or incorrect GTIN"; older accounts and many forum threads still call it "Limited performance due to missing identifiers". It does not switch the product off, but it holds it back. This page explains what triggers it and how to clear it for one product or a whole catalog.

Diego Nijboer · WISEPIMLast updated:

Short answer

Give each affected product its manufacturer's GTIN, or a brand plus an MPN when no GTIN exists. Only for products that truly have none of these, such as handmade or vintage items, set identifier_exists to no. Fix one product under Products, Needs attention, or download the affected list, correct your data and upload it again. Changes can take a while to show.

What this issue means

Google uses unique product identifiers (a GTIN, or a brand together with an MPN) to match your offer to the product it already knows. When one or more of those values is missing or not recognized as valid, Merchant Center raises this issue. Whether a product needs identifiers depends on the country you sell in and on its Google product category.

The product stays eligible, which is why the warning is easy to ignore. Google's help page lists it as limited performance: the offer competes with less information than offers that carry a GTIN. If you are not sure which barcode number you have, read GTIN vs UPC vs EAN first.

DetailValue
Issue in Merchant CenterMissing or incorrect GTIN
Also shown asLimited performance due to missing identifiers: GTIN [gtin], MPN [mpn], brand [brand]
Attributegtin [gtin]
EffectThe product can still show, but with limited performance until it has a valid GTIN, or a brand and MPN.
CheckedAgainst Google Merchant Center Help on 11 October 2026

Common causes

  • The gtin field is empty, and brand or mpn is missing as well.
  • A submitted GTIN fails validation, for example because of a typo in the check digit.
  • The product's category or target country expects identifiers you did not send.
  • A one-of-a-kind, custom or vintage product was sent without identifier_exists set to no.
  • Your shop or feed tool keeps the barcode in a field that is not mapped to gtin.

How to fix it, step by step

  1. In Merchant Center, open Products and the Needs attention tab, and filter on this issue to see every affected product.
  2. For a handful of products: open the product, choose Edit product, add the manufacturer's GTIN (or a brand and MPN) and save.
  3. For many products: download the list of affected products as a CSV file and match it against your product data by ID.
  4. Look up the real GTIN for each product on its packaging or in the supplier's data. Never invent one or reuse another product's code.
  5. Run each GTIN through a check digit test, such as the EAN/GTIN validator, before you upload.
  6. Where no GTIN exists, send brand and mpn. Only when a product has no GTIN, no MPN and no brand, set identifier_exists to no.
  7. Upload the corrected data the way you normally do (file, scheduled fetch, API or your platform's app) and check Needs attention again after the next processing run.

Free tool

Check a product against Google Shopping rules

Enter one product's title, description, price, GTIN and image link. The checker lists the errors and warnings Merchant Center's core requirements would raise, before you upload.

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How to prevent it

  • Make GTIN, brand and MPN part of the minimum data a new product needs before it can be published.
  • Ask suppliers for barcodes in their product sheets, per variant, not per parent product.
  • Validate check digits when data comes in, not when Google rejects it.
  • Keep a short, documented list of products that genuinely have no identifiers, so identifier_exists is never used as a shortcut.

How WISEPIM helps

WISEPIM stores EAN, UPC, MPN and brand on every product and variant. The Google Shopping rule pack in Quality Guard warns when brand, MPN or EAN is missing and blocks a GTIN with an invalid check digit, so you see the gap before the product is sent.

The Merchant Center connection only sends a GTIN when its check digit is valid, and sends brand and MPN alongside it. If you publish through Feed Hub instead, its Google Shopping feed computes identifier_exists for you: it writes no only when GTIN, MPN and brand are all empty.

Sources

Vendor documentation we read for this guide, as of October 2026. Features and names change, so check the current documentation before you decide.

Frequently asked questions

No. The product stays eligible, but Google treats it as limited performance until it has a valid GTIN, or a brand and MPN. Fixing it is still worth the effort for products that have a barcode.

Only if you are the manufacturer and that number is the part number you assign to the product. An MPN is the manufacturer's part number, not your internal stock code for a product someone else makes.

Only for products that have no GTIN, no MPN and no brand, such as one-of-a-kind, custom or vintage items. Setting it for a product Google knows has a GTIN causes a separate disapproval called Incorrect product identifier.

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