What Is Marketplace Integration and Why Do You Need It?

The short answer to the question of what marketplace integration is: it connects the seller system of a marketplace such as Trendyol, Hepsiburada, n11 or Amazon with your product, stock, order and invoice records through an interface called an API. Thanks to this connection, information flows automatically between the two systems instead of being entered manually, panel by panel.

What is marketplace integration, and how does it work?

Marketplaces offer sellers an API (application programming interface) so they can perform tasks such as uploading products, updating stock, retrieving orders and sending invoices programmatically. The integration software calls this API at set intervals or when an event occurs: it retrieves a new order when one comes in, sends the new quantity when stock changes, and links the invoice to the order once the invoice is issued.

Each marketplace's API uses different field names and rules. For example, on Trendyol a barcode can be at most 40 characters, a product title is limited to 100 characters, and in the order data the seller discount and the Trendyol discount come in separate fields. The integration's job is to convert your single product and order record into the format each marketplace requires.

What data flows?

We cover the details of stock flow in our article what is stock synchronization and the shipping side in what is shipping integration. You can find the move from order data to invoicing in our guide automatic e-invoices (e-Fatura) from marketplace orders.

Why do you need it?

• It prevents overselling: If the same product is sold on multiple channels and stock is updated manually, a product that has sold out on one channel keeps selling on another.
• It helps you meet invoicing deadlines: In Türkiye, an invoice must be issued within 7 days of delivery of the goods at the latest; as order volume grows, manual tracking gets harder.
• It reduces manual copying errors: Transferring an address, tax number or amount from the panel to the invoice by hand increases the risk of errors.
• It makes it easier to keep up with platform changes: Marketplaces update their APIs regularly. For example, according to Trendyol's developer announcement, the old order service is being retired on October 15, 2026; details are in our article Trendyol API October 2026 changes.

What is an API key, and how do you protect it?

The API key and the API secret are the credentials that allow software to connect to the marketplace API on behalf of your store. On most marketplaces they are obtained through the seller panel and used together with the seller or store ID. Anyone who has these credentials can access and change the product, price, stock and order information in your store.

That is why you should protect your API key as carefully as your panel password:

• Enter the key only on the own screen of an integration provider you trust; do not share it by email, messaging app or screenshot.
• Never give anyone your panel username and password instead of an API key.
• Renew the key when an employee leaves or when you switch integration providers.
• If you suspect a leak, renew the key immediately and check price and stock changes from the last few days.
• Ask your provider how it stores keys and for what purpose it processes customer data.

Where the key is created and how it is renewed varies by marketplace; check the help page of your seller panel for the current steps.

What should you look for when choosing an integration?

• Support for all the marketplaces you sell on and for your own website
• The ability to match variants and barcodes on a per-channel basis
• The ability to issue the invoice as an e-invoice or an e-archive invoice (e-Arşiv) depending on your and the buyer's e-invoice status, and to pass it on to the marketplace
• Clear visibility of error logs (stock that failed to send, rejected products)
• Timely updates for marketplace API changes

For our other articles on marketplace management, take a look at the marketplace category.