Fix Common GTIN and Product Identifier Errors in Your Shopping Feed

In the competitive landscape of e-commerce, your product feed is the digital backbone of your advertising strategy. It’s the critical link between your inventory and platforms like Google Shopping, Facebook, and Amazon. A perfectly optimized feed can lead to soaring visibility and sales. Conversely, a feed riddled with errors can cause product disapprovals, wasted ad spend, and immense frustration. Among the most frequent and impactful issues that merchants face are GTIN errors.

Product identifiers are the universal language of global commerce, and the Global Trade Item Number (GTIN) is the most important dialect. When these identifiers are incorrect, missing, or improperly formatted, shopping channels can't accurately categorize or display your products. This not only hurts your performance but can lead to account-level warnings.

This guide will serve as your comprehensive resource for understanding, identifying, and resolving the most common GTIN and product identifier errors. By mastering your product data, you can ensure your feed is a powerful asset, not a persistent liability.

What Are GTINs and Why Do They Matter So Much?

Before diving into the fixes, it's crucial to understand what GTINs are and why they hold so much weight in the e-commerce ecosystem. A GTIN is a globally unique number used to identify trade items. It’s the number you find under the barcode on a product's packaging. Depending on the product and region, GTINs come in several formats:

• UPC (Universal Product Code): A 12-digit number predominantly used in North America.
• EAN (European Article Number): A 13-digit number primarily used outside of North America.
• JAN (Japanese Article Number): An 8 or 13-digit number used in Japan.
• ISBN (International Standard Book Number): A 10 or 13-digit number used exclusively for books.

For shopping channels, GTINs are the definitive key to understanding exactly what you're selling. Here’s why they are non-negotiable for most products:

• Accurate Product Matching: Google uses GTINs to pull product details, images, and customer reviews from its vast catalog. A correct GTIN ensures your product is matched with the right listing, enhancing its credibility and appeal.
• Enhanced Ad Placement: Products with correct GTINs are eligible for more prominent and diverse ad placements, including comparison listings and SERP features. This directly translates to increased visibility.
• Improved Performance: By understanding the exact product, platforms can show your ads to more relevant users, leading to higher click-through rates (CTR) and better conversion rates.
• Avoiding Disapprovals: Most major platforms mandate GTINs for any mass-produced item. Failing to provide one, or providing an incorrect one, is a fast track to product disapproval.

Identifying and Fixing Common GTIN Errors in Your Feed

The first step to a healthier feed is diagnosing the problem. In your Google Merchant Center account, the "Diagnostics" tab is your best friend. It will flag products with issues and provide specific error messages. Let's break down the most prevalent GTIN errors and how to resolve them.

1. Missing GTIN [`identifier_exists` is 'true']

This is one of the most straightforward GTIN errors. The platform recognizes that your product is a type that should have a GTIN (e.g., a branded sneaker), but the GTIN attribute in your feed is empty. You've indicated that an identifier exists, but haven't supplied it.

• Why it happens: This is often a data entry oversight, an incomplete export from your e-commerce platform, or a failure to collect this information from your supplier.
• How to fix it: The solution is to find the correct GTIN. Check the product's physical packaging or barcode. If you don't have the product on hand, contact the manufacturer or your supplier directly. As a last resort, barcode lookup tools online can sometimes help, but always verify the number against an official source if possible. Once you have the correct GTIN, update the corresponding product in your feed.

2. Invalid GTIN Value

This error occurs when the number you’ve provided in the GTIN field doesn't conform to the standard GTIN structure. It might be too short, too long, contain letters, or have an incorrect "check digit"—the final digit in the sequence that mathematically validates the rest of the number.

• Why it happens: Simple typos are the most common cause. Other reasons include accidentally populating the GTIN field with an internal SKU, a Manufacturer Part Number (MPN), or just a random number. For example, submitting "123456789" for a UPC is invalid because a UPC must have 12 digits.
• How to fix it: First, meticulously re-check the number against the product's barcode for typos. Ensure you are not including any dashes or spaces. To be certain, use an online GTIN validation tool. These tools can instantly tell you if the number's structure and check digit are correct. If the number is fundamentally wrong, you will need to source the correct GTIN from the manufacturer.

3. Incorrect GTIN for the Product (or Variant)

This is a more subtle error. The GTIN you’ve submitted is structurally valid, but it’s assigned to the wrong product. A classic example is using the GTIN for a blue t-shirt (size medium) on the listing for the same t-shirt in red (size large).

• Why it happens: This is a frequent issue with products that have variants (size, color, material). It can be caused by copy-paste errors during data entry or a flawed logic in how your feed is generated, where a "parent" product's GTIN is applied to all its "child" variants.
• How to fix it: This requires a careful audit of your product data. Remember this critical rule: every unique, sellable variant must have its own unique GTIN. You cannot reuse a GTIN across different colors or sizes. You must map the correct GTIN to each specific variant in your source data (e.g., your Shopify or Magento platform) so that your feed generation tool pulls the right identifier for each item.

4. Ambiguous GTIN (Used by Multiple Products)

This error is closely related to the one above. It's flagged when you submit the exact same GTIN for two or more different products in the same feed and target country. For example, using the same GTIN for both a pair of headphones and a computer mouse.

• Why it happens: This is almost always a data management error, where a GTIN was incorrectly duplicated across multiple product rows in your spreadsheet or database.
• How to fix it: Isolate the duplicated GTIN. A feed management platform like Feedance can make this easy by allowing you to sort and filter your products by GTIN. Once identified, you must find the correct, unique GTINs for each of the affected products and update your feed accordingly.

5. Unsupported Value [`identifier_exists` is 'false']

This error message is a bit of a curveball. Here, you've explicitly told Google that the product does not have a GTIN by setting the `identifier_exists` attribute to 'false'. However, Google's system has found evidence that the product (based on its brand and category) should have one.

• Why it happens: Merchants often use `identifier_exists`:`false` for products that are custom-made, vintage, or one-of-a-kind. This error occurs when that value is incorrectly applied to mass-produced items from established brands. For instance, you can't sell a new Nike shoe and claim it has no identifier.
• How to fix it: Be honest in your data. The `identifier_exists`:`false` attribute should only be used for genuinely unique items that have never been assigned a GTIN. For all other products, you must do the work to find the correct GTIN and MPN. Change the attribute to `true` (or remove it, as `true` is the default) and provide the valid identifiers.

A Proactive Strategy for Preventing GTIN Errors

Fixing errors reactively is necessary, but preventing them from happening in the first place is far more efficient. A proactive approach to data management will save you countless hours and prevent lost revenue.

Establish a "Single Source of Truth"

Your product data should live in one central, reliable location, whether that's a PIM (Product Information Management) system, an ERP, or even a well-structured master spreadsheet. When data is scattered across multiple files and departments, inconsistencies and GTIN errors are inevitable.

Implement Data Validation Rules

Don't wait for Google to tell you there's a problem. Use a robust feed management platform to create rules that automatically validate your data before it's submitted. For example, you can set up a rule that flags any product where the GTIN field does not contain exactly 12 or 13 digits, or a rule that alerts you if the same GTIN is used more than once.

Work Closely with Suppliers

The best data comes directly from the source. Establish a clear process for receiving complete and accurate product information, including GTINs for all variants, from your manufacturers and suppliers. Make this a required part of your onboarding process for new products.

Beyond GTINs: A Note on MPN and Brand

While GTIN is king, two other identifiers are crucial: Brand and MPN (Manufacturer Part Number). For most products, Google requires at least two of these three identifiers.

• Brand: The product's brand name. This must be accurate and consistent.
• MPN: A unique alphanumeric code assigned by the manufacturer to identify a specific product among their other products.

If you truly cannot provide a GTIN (for example, for some private label goods or industrial parts), a strong combination of Brand and MPN is your next best option. However, never invent these numbers. Providing false identifiers is a policy violation that can lead to account suspension.

Navigating the complexities of product feeds can seem daunting, but resolving GTIN errors is one of the highest-impact activities you can undertake to improve your shopping campaign performance. These identifiers are not just arbitrary numbers; they are the linchpin that connects your products to a global marketplace of eager buyers.