Use an affected-products CSV checker to group invalid GTIN rows by number shape, duplicate barcode, Shopify barcode or WooCommerce GTIN, feed app mapping, and GMC rule owner before bulk edits.
Use this when you need to test CSV rows for GTIN length, non-numeric values, failed check digits, duplicate identifiers, or SKU-as-GTIN patterns before source-owner review.
Validate GTIN rowsLoad affected-products sampleUse this when you need to see how Merchant Center affected rows and Shopify or WooCommerce product rows are grouped before uploading private CSVs.
Load the identifier sampleReviewed GTIN snapshotUse this when Shopify barcode, feed app mapping, Merchant Center diagnostics, or public product evidence disagree.
Prefill the reviewed requestSend store URL for Feed/GMC owner mapPrivate affected CSV rows can wait for the reply thread when product counts, feed fetch timing, app mapping, or GMC final attributes may be overwriting the submitted GTIN.
Send store URL for Feed/GMC owner mapShopify barcode sync pathUse this when Shopify variant barcode is filled but Merchant Center still receives blank, stale, invalid, duplicated, or transformed GTIN values.
Trace barcode sync evidenceDo not bulk rewrite barcode fields first. For Google Merchant Center invalid GTIN warnings, join the affected-products CSV to your catalog export and decide whether the owner is GTIN shape, Shopify barcode, WooCommerce GTIN field, feed app mapping, Merchant Center rule, or product identity proof.
Validate item ID, submitted GTIN, digit-only format, GTIN-8/12/13/14 length, check digit, and duplicates before editing Shopify or WooCommerce product data.
Run bulk GTIN validatorTrace the source field nextIf the value looks valid in Shopify or WooCommerce but invalid in Merchant Center, compare affected-products rows, product exports, feed app mapping, supplemental feeds, and GMC rules.
Open identifier CSV checkerEscalate only when evidence conflictsSend the store URL for a 1-page Feed/GMC owner map when many variants are affected or Shopify barcode, feed app, GMC diagnostics, and public product evidence disagree. Private affected CSV rows can wait for the reply thread.
Send store URL for Feed/GMC owner mapInvalid GTIN issues are row-level source-ownership problems. A useful page should let users test affected rows, separate number-shape errors from source-field conflicts, and understand where the bad value originates before changing feed rules.
Shopify, WooCommerce, and feed-app users dealing with Google Merchant Center affected-products CSV exports or GTIN disapproval warnings.
Invalid GTIN warnings can start in Shopify barcode fields, WooCommerce GTIN fields, feed app mappings, supplemental feeds, or Merchant Center feed rules. Pick the source owner before changing hundreds of product rows.
You need a bulk GTIN validator for CSV rows to check UPC, EAN, ISBN, GTIN-14 length, non-numeric values, check digits, or duplicate GTINs.
Run the GTIN validator CSV toolValidate affected rowsThe affected-products CSV contains invalid length, failed check digit, duplicate barcode, non-numeric GTIN, SKU-as-GTIN, or placeholder barcode patterns.
Run the identifier CSV checkerMissing identifiers insteadMerchant Center also says GTIN, MPN, brand, or identifier_exists is missing, not just invalid.
Use the missing identifier decision treeFeed ownership conflictShopify barcode exports look correct, but Google receives blank, stale, transformed, or overwritten GTIN values.
Send store URL for the 1-page Feed/GMC owner mapSuspension or policy contextInvalid GTIN appears together with account review, suspension, appeal, misrepresentation, or merchant trust evidence.
Build the suspension evidence packThe report connects each visibility problem to crawl evidence, AI answer samples, competitor risk, and a concrete repair step.
A malformed GTIN weakens Merchant Center product identity and can lead to affected-products warnings or limited performance.
If SKU is mapped into GTIN or MPN without verification, products can inherit internal identifiers that Google cannot trust.
Editing Merchant Center rules may silence one symptom while leaving Shopify, WooCommerce, or feed-app data inconsistent.
Run the free GTIN CSV checker sample first. Send the store URL first for a 1-page Feed/GMC owner map when affected rows, Shopify or WooCommerce exports, feed app mapping, Merchant Center rules, or GMC diagnostics disagree. Private affected CSV rows can wait for the reply thread.
Use this packet when Merchant Center flags invalid GTIN rows and you need to prove whether the bad value starts in the source catalog, feed transform, Merchant Center rule, or public product identity evidence.
Use this when affected rows contain wrong GTIN length, failed check digit, letters, duplicate barcodes, SKU-as-GTIN, stale submitted values, or feed-rule overrides.
Attach Merchant Center affected-products CSV, Shopify or WooCommerce product export, feed app mapping screenshot, supplemental feed or Merchant Center rule screenshot, and sample product URLs with barcode or manufacturer proof.
Decide whether the repair owner is barcode source field, WooCommerce GTIN field, feed app mapping, supplemental feed, Merchant Center rule, or public product proof.
This preserves what Google grouped as invalid before rows are edited or warnings are cleared.
This shows whether the store catalog is the source of the invalid value or whether the catalog already has a usable barcode.
This identifies whether a correct catalog value is being overwritten, transformed, delayed, or replaced by a rule.
This prevents treating a valid-looking number as a verified product identifier when public evidence does not support it.
Invalid GTIN evidence packet:
Merchant Center invalid row state: item ID, issue name, submitted GTIN, affected attribute, destination, severity, last seen date, invalid pattern.
Catalog barcode source evidence: Shopify barcode or WooCommerce GTIN, SKU, product/variant ID, brand/vendor/supplier/manufacturer field, blank or SKU-as-GTIN rows.
Feed transform evidence: feed app GTIN mapping, generated feed row, supplemental feed value, Merchant Center feed rule.
Public product identity proof: product URL, visible brand/manufacturer proof, package or barcode evidence, rows where assignment is uncertain.
Decision needed: barcode source field, WooCommerce GTIN field, feed app mapping, supplemental feed, Merchant Center rule, or public product proof.Google can reject or limit products when the submitted GTIN is malformed, copied from an internal SKU, or overwritten by a feed rule. The first step is to inspect the affected rows, not to rewrite every product manually.
UPC, EAN, GTIN-8, and GTIN-14 have specific digit lengths. Short values such as 12345 are not usable GTINs.
A value can have the right length but fail the check digit. That usually means a typo or copied internal number.
Shopify variant barcode is commonly mapped into GMC GTIN. If that field is empty or wrong, the feed inherits the problem.
A feed app, supplemental feed, or Merchant Center rule can overwrite the correct source value with a stale one.
Do not treat every invalid GTIN as a Merchant Center-only problem. The right repair depends on where the value is generated.
Check variant barcode first. Do not copy SKU into barcode unless it is a real manufacturer barcode.
Check the GTIN custom field or product feed plugin mapping before editing Merchant Center rules.
Review field mapping and transformations. Look for SKU-to-GTIN mapping, stale supplemental feeds, or copied placeholders.
Use feed rules only when the source platform cannot expose the correct field directly.
The safest repair is the one closest to the source of truth. Use Merchant Center rules only after the ecommerce platform or feed owner cannot expose the correct identifier cleanly.
Fix this when the barcode field contains SKU, supplier code, placeholder values, letters, wrong-length values, or duplicated barcodes across unrelated variants.
Fix this when GTIN lives in a product attribute, custom field, or feed plugin field that is blank, malformed, or not mapped to the submitted GTIN.
Fix this when the app maps SKU to GTIN, applies transformations, sends stale values, or chooses a variant-level field different from the catalog export.
Use this only when the source platform cannot send the right value directly, or when a supplemental feed/rule is intentionally correcting a known source limitation.
Obvious GTIN shape errors can be fixed from the free checker output. A 1-page Feed/GMC owner map is useful when the same warning touches many variants, the Shopify export and GMC affected rows disagree, or a feed app or Merchant Center rule may be overwriting correct product data.
Start a Feed/GMC owner map before changing GTIN fields across hundreds of variants, bundles, or copied product rows.
Use the owner map when Shopify barcode values look correct but Merchant Center receives blank, stale, or transformed GTIN values.
Attach feed app mapping screenshots and Merchant Center rule evidence before deciding whether to edit Shopify, a supplemental feed, or GMC rules.
Include sample product URLs when barcode, brand, manufacturer, or product identity claims need to match visible buyer evidence.
The checker can validate shape and check digit. It cannot prove the GTIN is officially assigned to your brand or product.
Group rows by item ID, issue title, submitted GTIN, affected attribute, destination, severity, and invalid pattern. Then join those rows to Shopify, WooCommerce, or feed-app product exports before changing barcode fields.
Compare the source catalog value, generated feed row, supplemental feed, Merchant Center rule, and final received GTIN for the same item ID. The first layer where the value changes, disappears, or becomes malformed is the repair owner.
Common causes include wrong length, failed check digit, letters in the barcode field, copied SKU values, placeholder barcodes, or feed rules that override the correct source value.
Start with the variant barcode field. Then check the Google & YouTube app, feed app mapping, and any Merchant Center feed rule that may override GTIN.
No. SKU is usually an internal store identifier. GTIN is a manufacturer/global trade item identifier such as UPC or EAN.
No. A valid check digit only confirms the number shape. It does not prove GS1 ownership, policy compliance, or account approval.
Request one when the same invalid GTIN warning affects many variants, Shopify barcode exports and GMC affected rows disagree, or a feed app, supplemental feed, or Merchant Center rule may be overwriting correct source data. Send the store URL first; private affected CSV rows can wait for the reply thread.
Run the free GTIN CSV checker sample first. Send the store URL first for a 1-page Feed/GMC owner map when affected rows, Shopify or WooCommerce exports, feed app mapping, Merchant Center rules, or GMC diagnostics disagree. Private affected CSV rows can wait for the reply thread.