How do I use GTINs and MPNs for better product matching in feeds?

Every time I set up a new product feed, I’m struck by how a small, seemingly technical detail, like a GTIN (Global Trade Item Number) or an MPN (Manufacturer Part Number), can make or break my product listings.

I’ve seen first-hand how these identifiers influence everything from search visibility to conversions across major eCommerce channels like Google Shopping, Amazon, and eBay.

In this post, I share my approach to GTINs and MPNs, why they matter, and the practical steps (and pitfalls) you should know to get the best performance from your feed.

Why GTINs and MPNs Matter

I’ll get right to it: GTINs and MPNs improve product matching and overall feed performance. They act like a passport for your products, telling platforms exactly which item you’re selling. In my work, I’ve consistently seen how listings with complete identifiers perform better than those missing these key pieces of data.

GTINs are unique and recognized worldwide. They help platforms match your product to extensive catalogs—it’s a language that all eCommerce channels understand. If a GTIN isn’t available, I rely on the MPN along with the brand name.

This combination typically helps match the product accurately, but the GTIN remains the standard choice. Platforms like Google encourage or require GTINs when available; otherwise, you risk rejected listings or reduced ad delivery.

Pro tip: GTINs and MPNs are only a small amount of the attributes that are present in a product feed, to add the rest it is usually much easier to do with a feed optimization tool.

Before we get too in-depth with this, it is probably worth mentioning how you even get these into your feed or onto your product pages. In some e-commerce platforms like Shopify you can insert them manually.

This however might be a tedious process, the other option is to upload your GTINs and MPNs in Google Merchant Center as a supplementary feed and attach them to your main feed.

The Power of GTINs in Product Feeds

I’ve observed that GTINs have a significant impact on Google Shopping. Google maintains a vast product catalog and if your feed contains the correct GTIN for each product, you benefit from:

1. Precise Identification. Google matches your product directly to its database. This reduces mismatches, such as your product mistakenly appearing under another seller’s listing.
2. Improved Listing Quality. Providing complete GTIN data tends to boost feed approval rates. Google’s systems favor product listings with all the necessary identifiers, which can help them achieve better placement in Shopping results.
3. Enhanced Visibility. Ever notice how some products appear grouped in aggregated listings? That happens when the system recognizes multiple sellers for the same product, made possible through accurate GTINs.

Data from Google indicates that products matched in their catalog can receive up to 40% more clicks. That represents a big opportunity you should consider.

Using MPNs as a Viable Alternative

Sometimes, I come across products without an official GTIN—perhaps they’re custom-made, privately labeled, or simply older stock where the manufacturer never assigned one. This is where MPNs come into play. MPN stands for Manufacturer Part Number. While not universal like a GTIN, it remains a recognized method to confirm a product’s identity.

A few pointers when relying on MPNs:

• Ensure your MPN is genuine and not a number you invented. Incorrect labeling can lead to feed rejections.
• Pair the MPN with an accurate brand name. This combination is essential if a GTIN is missing.
• Remember that platforms still give preference to GTIN data. If you have a GTIN, include it. If not, the MPN is the next best option.

How GTIN and MPN Data Boost Visibility and Conversions

I don’t usually make a big deal out of things, but let me share a quick story that shows the importance of GTIN and MPN data.

A few years ago, a client was launching a product line on Google Shopping. Their feed contained only partial GTIN data, and many products were missing these unique codes. The feed got approved, yet visibility and traffic were very low. Products rarely appeared for the high-intent keywords we targeted, and scaling was difficult.

After tracking down the GTIN for each item—which involved significant coordination with suppliers—and updating the feed, the change was immediate:

• Impressions jumped from only a few per day to hundreds.
• Clicks increased, and within a few weeks, we saw a 3,400% increase in visibility for products that had previously underperformed.
• Conversions improved steadily as a result of better search result positioning and improved matching accuracy.

Even when using MPN as an alternative, including a unique product identifier clearly pays off.

A Quick Data Check

Industry experts and Google both report improvements when GTINs and MPNs are provided:

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These trends hold true across many product categories, whether electronics, apparel, or specialized industrial supplies.

Acquiring and Validating GTINs

There are times when you don’t know your product’s GTIN, especially if you’re a reseller or dealing with older products that never had barcodes.

Steps to Acquire GTINs:

1. Check Product Packaging or Labels. Often, a UPC (in North America) or EAN (in Europe) is printed on the packaging. These are forms of GTIN (a UPC is a GTIN-12; an EAN is a GTIN-13).
2. Ask the Manufacturer or Supplier. If the code isn’t on the packaging, your supplier or the brand might be able to provide the correct GTIN.
3. Purchase Official GTINs for private label products. Organizations like GS1 let you buy barcodes if you’re the brand owner. This process ensures the identifiers are legitimate.

I avoid guesswork at all costs. If you come across an “online GTIN generator,” consider that a warning sign. Using randomly generated GTINs is not recommended and can result in feed disapprovals.

Validating Existing GTINs

Sometimes a product listing includes a GTIN, but it’s not certain that it’s correct. To check:

• Use the GS1 Check Digit calculator to confirm the structure of the number.
• Cross-check with the brand or supplier if there’s any uncertainty.
• Bear in mind that older or unofficial barcodes might not pass a GS1 check, leading to errors in your feed.

Step-by-Step Implementation in Your Feed

Adding GTINs and MPNs in your feed need not be complex. Here is my common workflow:

1. Gather All IdentifiersFor each product, list out potential barcodes, GTINs, or MPNs from your inventory or data provided by brands.

2. Map to Feed Fields

• In Google Merchant Center, map GTIN data to the “gtin” field. MPN data goes to the “mpn” field, and include “brand” if you have that information.
• On Amazon, you might need to fill in fields like “product ID type” (for example, UPC or EAN) and “product ID.”

3. Optimize Titles and Descriptions (if needed)While not always necessary, including brand or model references in titles or descriptions can help with consistency and matching.

4. Submit the Feed and MonitorAfter submitting the feed, keep an eye out for errors. Google and other platforms will notify you of any conflicts or issues with the GTIN or MPN data.

5. Tweak and RefineIf you notice any mismatches or flagged products, correct them immediately. Sometimes a brand might have multiple MPNs for the same item or a single GTIN used for various options, which can cause confusion.

Remember to update your feed regularly. If a product changes or a new GTIN is introduced, make the necessary adjustments to maintain accuracy.

Common Pitfalls and How to Avoid Them

Not everything goes smoothly with GTINs and MPNs. Here are some common issues:

• Using Fake or Random GTINs
  Do not use numbers that do not conform to official GS1 standards. Incorrect numbers can lead to flagged or rejected listings and may damage your reputation.
• Mislabeling MPNs or GTINs
  Some mix up MPNs with internal SKUs. An MPN is assigned by the manufacturer, not created in-house. Confusing the two can result in mismatches.
• Forgetting Brand Data
  When relying on MPN in the absence of GTIN, be sure to include the brand attribute. Without it, the product’s identification may be incomplete.
• Not Updating When Things Change
  If a supplier revises the GTIN, update your feed promptly. Outdated data can cause ongoing issues with product matches.

What If I Sell Custom or Handmade Products?

Custom or handmade items may not have a GTIN, and that is acceptable. Platforms like Google Shopping allow you to mark such products accordingly. Typically, you would:

1. Set the “identifier_exists” field to FALSE (or “no”) in your feed.
2. Provide any available brand name for your custom line.
3. Include an MPN only if it is officially recognized for the item.

Keep in mind that feeds without recognized GTINs might attract fewer impressions because the system has a harder time categorizing and recommending your items. I have worked with artisans who have found success, but understand that the playing field is different from that of large brands with official GTINs.

GTINs and MPNs on Omnichannel Platforms

Google Shopping is not the only platform where these identifiers matter. When working with merchants on Amazon, eBay, or other marketplaces, it is important to remember that these codes are used everywhere:

• Amazon primarily uses UPC (a type of GTIN) to match products to its catalog. If you list a branded product that already exists on Amazon, you need the correct UPC.
• eBay requires GTIN or MPN to categorize products effectively. For niche or collectible items, MPN or brand information may be more critical.
• Other channels such as Walmart Marketplace and smaller comparison engines also request these identifiers for better matching.

Once you have GTINs and MPNs sorted, apply them consistently across every channel.

Impact Stats and Performance

A quick look at the benefits:

I have noticed these trends repeatedly across various product types.

Real-World Case Study: 3,400% Growth

A while back, I worked with a small kitchen appliance company that had scattered and partial GTIN data. It took about a week of coordinating with suppliers to gather the correct codes.

After updating the feed:

• Impressions jumped from 66 in one week to over 1,800 in the next.
• Sales increased as more buyers saw the listings during targeted searches.

Though other optimizations were in place, adding the GTIN data was the key change that allowed the feed to perform better.

Best Practices and Expert Tips

After managing many feeds, here is a brief list of practices that I stick to:

1. Use All Available Identifiers
   If you have a GTIN, include it. Otherwise, use the combination of MPN and brand. Do not leave these fields blank if you have the information.
2. Be Consistent Across Platforms
   Whether it is Amazon, eBay, Google Shopping, or another marketplace, use the same GTIN or MPN for the same product. Consistency prevents duplication or matching issues.
3. Match GTIN with Product Variations
   If you offer variants (different sizes, colors, or bundles), check whether each variant has a unique GTIN or if they are grouped. Mistakes in this area can confuse search results and hurt conversions.
4. Monitor Your Feed Regularly
   Check your Google Merchant Center or Amazon Seller Central often. Error notifications regarding identifiers can occur at any time.
5. Secure Official GTINs for Private Label Products
   If you are building your own brand, do not use unofficial barcodes. A legitimate assignment from GS1 is the safest option.

Potential Roadblocks to Be Aware Of

Some challenges may arise:

• Products with Multiple Barcodes. Some manufacturers assign multiple barcodes for the same item in different regions. Decide which one to use and keep it consistent.
• Custom or Handmade Items. These products may lack GTINs and will not perform in product matching as well as mass-produced items.
• Incomplete Data from Suppliers. Without complete GTIN information from your supplier, you might have to leave some product lines out of your feed.