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Fix guides · AI readability

Your products have no GTIN, EAN or MPN

Without GTIN/EAN codes, Google Merchant Center limits your listings and AI assistants cannot match your product to the same product elsewhere. Where to add GTINs in WooCommerce and how they reach schema and feeds.

Impact: High We fix this in AI Visibility Setup — €790 · Updated

The symptom

  1. Merchant Center warnings *Missing GTIN* / *Limited performance due to missing identifiers*.
  2. Schema shows no gtin13, gtin, gtin8, gtin14 or mpn field.
  3. Products imported from a supplier CSV that did not include barcodes.

Why it matters

A GTIN (the 13-digit EAN on the barcode) is the global identity of a product. Google uses it to place your offer on the product’s comparison page; AI assistants use it to confirm that your "Bosch GSR 12V-35" is the same item they found elsewhere, and to trust your price.

Since 2025 Google treats missing identifiers as a quality issue for branded products; unbranded or custom goods can declare identifier_exists = no instead.

How to check it yourself

  1. Open a product in WordPress admin → Inventory tab. WooCommerce 9.2+ has a native GTIN, UPC, EAN or ISBN field. Is it filled?
  2. Rich Results Test → Product → gtin13/mpn.
  3. Merchant Center → Products → Needs attention → identifier issues.

How to fix it

  1. Collect codes: from supplier price lists, packaging barcodes, or the manufacturer’s site. For own-brand products, buy GS1 codes; do not invent numbers.
  2. Enter them in the WooCommerce GTIN field (bulk import via CSV column GTIN, UPC, EAN, or ISBN or the REST API global_unique_id). Older stores can use Rank Math’s or Yoast’s GTIN fields, or a *Product GTIN* plugin.
  3. Confirm the SEO plugin outputs the value as gtin13 (13 digits) or gtin in schema, and map the same column to gtin in your Google/Microsoft/OpenAI feed.
  4. Where a product genuinely has no GTIN, output mpn + brand and set identifier_exists to no in the feed.

FAQ

Straight answers to the questions store owners ask

Do variations need their own GTIN?

Yes — each size/colour is a different barcode. WooCommerce 9.2+ supports the field on variations.

Can I use the supplier’s SKU as GTIN?

No. GTINs are numeric, 8/12/13/14 digits with a check digit. Invalid values cause feed disapprovals.

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