What Is a Barcode (GTIN, EAN)? How to Get a Barcode for Marketplaces

The short answer to what a barcode is: a barcode is a machine-readable representation, in the form of lines or squares, of the number that identifies a product. The number behind the product barcodes used in retail and on marketplaces is called a GTIN (Global Trade Item Number); its most common format in Türkiye is the 13-digit EAN-13. GTIN/EAN barcodes come from GS1, and GS1 is represented in Türkiye by the Union of Chambers and Commodity Exchanges of Türkiye (TOBB).

What is a barcode, and what do GTIN and EAN mean?

These three concepts are often confused:

In short, what the customer and the marketplace see is the barcode, and what systems match on is the GTIN number. The last digit of a GTIN is a check digit calculated from the other digits; a randomly made-up number usually fails this check.

A barcode is different from the stock keeping unit (SKU) that a seller sets for itself. Every seller of the same product may have a different SKU, but the product's GTIN is the same. We showed the difference in a table in our what is an SKU article.

How do you get a barcode for marketplaces?

The official way to get barcodes for products you manufacture or import under your own brand is the GS1 system. In Türkiye, GS1 is represented by TOBB. The process generally works like this:

1. Application to GS1 Türkiye: A membership application is made on behalf of your company.
2. Company prefix: With membership, a block of numbers specific to your company is allocated.
3. Product numbering: From within this block, you assign a separate GTIN to each product and each variant.
4. Printing the barcode: The number is printed as a barcode on the packaging or label.

For application requirements and current membership fees, check GS1 Türkiye's own announcements; since fees are updated from time to time, we don't give an amount here. If you sell another brand's product, you don't need to get a barcode; you use the manufacturer barcode on the product.

Barcode rules on Trendyol, Amazon and n11

Trendyol barcode rule

On Trendyol, the barcode field is limited to 40 characters, and the only special characters allowed are the period, hyphen and underscore. Each variant has its own barcode; a black size M and a black size L cannot carry the same barcode. If the product has a manufacturer barcode, entering it is important so that sellers of the same product are matched correctly. This matching also affects which seller is featured on the product page; for details, see our what is the buybox article.

Barcodes and barcode exemption on Amazon

On Amazon, most categories require a GTIN (EAN or UPC) when you create a new product page. If your product doesn't have a GTIN, for example if you sell a handmade or unbranded product, you apply for a barcode exemption. When you add an offer to an existing product page created by another seller, however, no GTIN is needed.

n11

n11's store support pages also state that GTIN/EAN barcodes come from GS1 and that GS1 is represented in Türkiye by TOBB. Getting a GS1 barcode for your own-brand products lets you use the same number across all channels, including n11.

Barcodes in multichannel selling

If you sell a product on Trendyol, Hepsiburada, n11 and Amazon, the same variant should carry the same barcode on every channel. That way, orders, stock movements and returns are consolidated in a single product record. You can change product titles according to each channel's rules, but the barcode and SKU should stay fixed; we explained how to do this in our marketplace product naming rules guide.