How to Add Barcodes and GTINs to Shopify Products in Bulk
Barcodes seem like a minor data field until products start getting flagged in Google Merchant Centre. Most merchants who import from suppliers discover the problem only after seeing "Limited performance due to missing identifier" on dozens of products in their Shopping feed. The barcode field in Shopify was populated during import, but with the supplier's internal SKU code rather than a valid GTIN.
Fixing a missing barcode on one product takes a few minutes. Fixing it on 300 products takes the better part of a working week, if you can find the correct GTINs at all.
This article covers what GTINs are, why imported catalogues commonly lack valid ones, what that costs you in Google Shopping visibility, and how to add barcodes to Shopify products in bulk using automated lookup rather than manual searching.
What Barcodes and GTINs Are
A barcode is the visual symbol scanned at point of sale or in a warehouse. A GTIN (Global Trade Item Number) is the numeric identifier encoded in that barcode. Shopify stores the GTIN in the Barcode field on each product and variant.
The most common GTIN formats are EAN-13 (the 13-digit standard used in Australia, the UK, and most international markets) and UPC-A (the 12-digit standard used in the United States and Canada). ISBN codes used for books are also a GTIN variant.
GTINs are assigned by GS1, the international standards body. Every retail product manufactured by a brand with a GS1 membership has a registered GTIN. Google and other platforms use that registration to verify product identity: when a GTIN is submitted, the platform checks it against the GS1 database to confirm it matches the product being listed.
Why Imported Products Often Lack Valid GTINs
The most common cause is supplier CSV formatting. Suppliers often populate the barcode column of their export files with internal product codes or SKUs rather than registered GTINs. These house codes are meaningful within the supplier's own system but do not exist in the GS1 database. When they land in Shopify's Barcode field, they look like barcodes but fail validation wherever barcode verification is required.
Marketplace imports introduce a related problem. Amazon ASINs and eBay item numbers are platform-specific identifiers, not GTINs. A product imported from an Amazon listing may have a valid ASIN in the product data but no EAN-13 or UPC-A in the correct field.
Some products genuinely have no registered GTIN. Custom-manufactured products, private-label goods, and products from small manufacturers who have not registered with GS1 fall into this category. These products cannot be given a GTIN because one does not exist in the GS1 system.
The practical result for most merchants importing from wholesalers: a portion of the catalogue has invalid codes in the Barcode field, a portion has nothing, and a smaller portion has legitimate GTINs that arrived correctly from the supplier.
What Missing GTINs Cost You in Google Shopping
Google Shopping requires valid GTINs for branded products where a GTIN exists in the GS1 database. Products submitted to Google Merchant Centre without a valid GTIN (when one should exist) receive a "Limited performance due to missing identifier" status. Google surfaces these products less frequently in Shopping results.
The "should exist" condition is important. Google checks whether a GTIN is registered for a product matching that title and brand. If a GTIN exists but was not submitted, the product is penalised. If no GTIN exists (a custom product), the product can be marked as custom and given an MPN (Manufacturer Part Number) instead. The problem arises specifically with branded products that have registered GTINs but whose Shopify Barcode field is blank or contains a non-GTIN code.
For merchants who import branded products from wholesalers, this affects a significant portion of the catalogue. Many such catalogues were imported with supplier SKUs in the Barcode field, meaning hundreds of products show in Merchant Centre with limited performance that could be resolved by filling in the correct GTINs.
The Solution
How Importier's Barcode Lookup Works
Importier's data enrichment feature includes automated barcode lookup as part of the enrichment pipeline. During the 14-step import wizard, data enrichment runs on each product in the import batch.
For each product, Importier searches for the registered GTIN using the product title, brand, and any other available identifiers. When a match is found in the GTIN database, Importier writes it to the Shopify Barcode field automatically. If an initial search does not return a confident match, Importier conducts a broader search across product data sources before concluding.
Products where no valid GTIN can be confirmed are flagged rather than guessed. These are typically custom or private-label products without a registered GTIN in the system.
- Search each product manually on manufacturer sites
- 3-5 minutes per product
- 15-25 hours for a 300-product catalogue
- Risk of entering an incorrect GTIN
- No batch tracking or audit summary
- Automated lookup runs across the full batch
- Minutes for hundreds of products
- Writes the GTIN directly to the Shopify Barcode field
- Products flagged when no confirmed match exists
- Enrichment summary with full results per run
Running Barcode Lookup on Existing Products
For merchants who already have products in Shopify without valid barcodes, the lookup runs retroactively through Importier's data enrichment panel. You do not need to re-import anything.
- 01Open Importier in your Shopify adminFrom Apps, launch Importier and navigate to Data Enrichment
- 02Select the products to targetFilter by collection, vendor, or SKU pattern to focus on products with blank or invalid Barcode fields
- 03Run the enrichmentImportier looks up the correct GTIN for each targeted product and populates the Barcode field where a match is confirmed
- 04Review the enrichment summaryThe report shows how many products received a barcode, how many were already complete, and how many could not be matched
The same enrichment run also fills other commonly missing fields: product weight, product type, HS code, and country of origin. Running it once across the catalogue addresses multiple data gaps simultaneously rather than requiring separate passes for each field.
What Happens After Barcodes Are Filled
Once Shopify's Barcode field contains a valid GTIN, the downstream effects resolve quickly.
Google Merchant Centre feed. Shopify's Google channel integration reads the Barcode field and submits it as the GTIN in the Shopping feed. On the next feed sync after the barcode is populated, the GTIN goes to Merchant Centre. Google verifies it against the GS1 database. If the GTIN is valid and matches the product, the "Limited performance due to missing identifier" status is removed and the product competes at full visibility in Shopping results.
Inventory and fulfilment. Warehouse management systems and 3PL (third-party logistics) providers that receive products into inventory by scanning barcodes now have scannable codes on every product. Receiving workflows that previously required manual entry for products without barcodes become fully scannable.
Supplier and wholesale alignment. When placing repeat orders with a supplier, GTINs are the common identifier across systems. Products with valid GTINs in Shopify match cleanly to the supplier's catalogue, reducing the risk of mismatched orders or incorrect variants being shipped.
Barcode-based product lookup. Third-party tools, POS integrations, and inventory reconciliation workflows that look up products by barcode work correctly across the full catalogue rather than only for the products that happened to arrive with valid codes.
Running enrichment once across the existing catalogue and enabling it on future imports produces a complete catalogue where every branded product that has a registered GTIN has that GTIN in its Barcode field.
When No Valid GTIN Exists
For custom-manufactured products, private-label goods, and items from manufacturers without GS1 registration, no GTIN exists to find. Searching any GTIN database returns no match because the product was never assigned a registered code.
Google Merchant Centre handles this category differently. For products where a GTIN genuinely does not exist, you mark the product as a custom item and provide an MPN (Manufacturer Part Number) or other unique identifier instead. Google does not penalise custom products for lacking a GTIN. The penalty only applies when a GTIN exists and was not submitted.
When Importier's barcode lookup returns no confirmed match for a product, the product is flagged rather than given a fabricated code. Filling the Barcode field with an incorrect value is worse than leaving it blank, because Google checks submitted GTINs against the GS1 database and will disapprove products submitted with invalid codes.
For truly custom products, the correct action is to mark them as custom and provide whatever manufacturer identifier is available. Products from suppliers who use internal codes (not GS1 GTINs) fall into this category, and their barcode fields should reflect that rather than containing the supplier's internal SKU.
Barcode Lookup as Part of the Full Import Workflow
Barcode lookup is most effective when it runs during the initial import rather than as a retroactive fix. Products that arrive in Shopify with valid barcodes already populated go directly to Google Shopping with complete identifiers. There is no period of limited performance while the fix is applied.
During Importier's 14-step import wizard, data enrichment (including barcode lookup) runs as one of the configuration steps before the import completes. You enable enrichment, set any context hints for niche or unusual products, and Importier fills missing fields including barcodes as part of the same operation that imports the products. The imported products arrive in Shopify already enriched.
Pair this with Importier's AI description generation and category metafields to cover the full set of product data fields that Google Shopping evaluates: valid GTIN in the Barcode field, unique descriptions, and structured category attributes.
Try Importier free at importier.app
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