How to Add Barcodes (EAN/GTIN) to eBay, Amazon and Shopify Listings

The terminology, quickly

The distinction that matters most day to day: a barcode identifies the product to the world; a SKU identifies it to you. They coexist — TSHIRT-BLK-M and 5012345678901 describe the same item for different audiences. Our SKU guide goes deeper on the internal side.

Where to get barcodes

Reselling branded products

Use the manufacturer's barcode — it's printed on the packaging. Never invent one, and never buy a new one for a product that already has a GTIN. Marketplaces match your listing to the existing catalogue entry using that number; a wrong one creates a duplicate listing or gets rejected.

Your own products

Buy from GS1(gs1uk.org in the UK). You purchase a company prefix and generate your own numbers within it. There's an annual licence fee based on turnover and how many barcodes you need.

Adding barcodes platform by platform

eBay

On a single listing, the barcode lives in the item specifics as EAN (or UPC/ISBN by category), near Brand and MPN.

• Branded new items in many categories require a GTIN — listings without one can be blocked or lose filtered-search visibility.
• For genuinely unbranded or handmade items, select "Does not apply". Don't enter a fake number.
• Adding a correct EAN helps eBay match your item to its product catalogue, which usually improves placement.

For many listings at once, use File Exchange with the relevant product-ID column — see our eBay bulk editing guide for the CSV mechanics and the leading-zero trap.

Amazon

Amazon is the strictest. In a flat file, barcodes go in external_product_id with external_product_id_type set to EAN, UPC or GTIN. Amazon validates against GS1 and checks the number belongs to the brand on the listing.

No barcode and making your own products? Apply for a GTIN exemption: Seller Central → search "GTIN exemption" → select category and brand → supply the evidence requested (typically images of the product and packaging showing your branding, or a letter from the manufacturer). Approval is per brand and category, and is required before you attempt to list. Full flat-file process in our Amazon bulk upload guide.

Shopify

Shopify doesn't require barcodes — it's your own store — but you should still fill the field:

• Product → scroll to the variant → Barcode (ISBN, UPC, GTIN, etc.).
• For variants, each has its own barcode field — a T-shirt in three sizes has three different EANs.
• In a CSV it's Variant Barcode. Format the column as text first (see our Shopify CSV guide).

Why bother if it's optional? Because barcodes are what let you scan stock in and out, and what other channels match on when you expand. Filling them now saves a painful retrofit later.

Etsy

Etsy has no barcode field in the way the others do — its equivalent identifier is the SKU field per listing and variation. Many Etsy sellers skip it entirely because Etsy doesn't force the issue, and then find they can't sync Etsy stock with anything. If you sell anywhere else too, fill the SKU on every Etsy listing and variation, using the same SKU as your other channels.

Bulk-adding barcodes to an existing catalogue

Retrofitting barcodes across hundreds of products is a data job, and the order matters:

1. Build the master list first. One spreadsheet: SKU, product name, barcode. Get this right before touching any platform.
2. Protect the barcode column as text in whatever spreadsheet program you use. This single step prevents most of the failures that follow.
3. Validate check digits. EAN-13 and UPC-A have a check digit; a mistyped barcode usually fails validation. Free online validators catch typos in seconds and save a rejected upload.
4. Update your central system first, then push to channels — rather than updating each marketplace separately and hoping they agree.
5. Upload per platform using File Exchange (eBay), flat file (Amazon), CSV import (Shopify).

If your catalogue lives in an inventory system, this collapses into one job: barcodes are stored once against each SKU and pushed everywhere. That's how Salync handles it — one catalogue holding SKU, barcode, cost and price, syncing to every connected channel, so a barcode added once appears everywhere rather than being entered three times.

Printing your own barcode labels

Separate job from marketplace identifiers: labels for your own shelves and picking. You need these when products arrive without scannable barcodes, or when you use internal location/bin labels.

• EAN-13/UPC-A for retail-standard products.
• Code 128 for internal codes — it encodes letters as well as numbers, so it can carry your actual SKU.
• QR where you want a phone camera to scan it easily.

Thermal label printers (Zebra, Brother QL, Dymo) are the practical choice — no ink, and they handle the small label sizes picking needs. Salync prints EAN-13, UPC-A, Code 128 and QR labels in any size directly from your catalogue, and the phone-camera scanner reads them back for stocktakes and goods-in — covered in our barcode inventory guide.