E-commerce · 11 min read · Updated:
What is marketplace integration? Stock and order management for Trendyol and Hepsiburada
If you sell the same product on your site and on three marketplaces, moving stock, prices and orders by hand stops working at some point. Integration does that moving regularly and under control.
In short
- Marketplace integration means product, stock, price and order data moving automatically between your system and the marketplace through an API.
- A Trendyol integration needs the Supplier ID, API key and API secret from the Trendyol seller panel.
- In the Heyşirket company panel, the Store › Marketplaces screen sends stock and prices to Trendyol, Hepsiburada, N11 and Amazon and fetches orders.
- Each channel has Off, Trial and Live modes; in Trial mode stock and prices are calculated but not sent to the channel.
- Marketplace connections are part of the store in the Professional plan; Trendyol payouts are matched to invoices in accounting.
The short answer to “what is marketplace integration?” is this: your product's stock, price and orders move between your system and the marketplace automatically, not by hand. With one channel you hardly need it. Once a second and third channel arrive, manual updating eventually turns into a mistake.
In this article we explain what integration carries, how a Trendyol API integration is set up, and what to watch in stock and price sync. Then we show how the same work is done in the Heyşirket company panel, with screen names.
Part 1 · Definition What is marketplace integration and what is it for?
Marketplace integration is the connection between a seller's own system and marketplaces such as Trendyol and Hepsiburada, built on the API the marketplace provides. An API is a door that lets two pieces of software send each other data securely; you don't share your seller panel password, you only enter keys created for the integration.
The connection takes on four jobs. Not every business needs all of them; most sellers start with stock and orders.
| What moves? | Direction | What does it prevent? |
|---|---|---|
| Stock | From you to the marketplace | Selling products you don't have |
| Price | From you to the marketplace | Old prices forgotten on a channel |
| Orders | From the marketplace to you | Copying orders one by one |
| Product (listing) | From you to the marketplace | Re-entering the same product on every channel |
Part 2 · Trendyol How do you set up a Trendyol integration?
For a Trendyol API integration you first get your integration details from the Trendyol seller panel. In the integration information section under your account details there are three values: the Supplier ID, the API key and the API secret. You enter these three values in the system you are integrating with.
The general flow of a Trendyol integration
Get the keys
Open the integration information section in the Trendyol seller panel and note your Supplier ID, API key and API secret. Don't share these by email.
Enter them and test
Enter the keys on the integration screen and test the connection. A successful test shows the details are correct; it doesn't change your products or prices yet.
Match products
Link each channel product to your own product record. Matching usually works by barcode; products without a barcode are skipped when stock is sent.
Watch in trial first
Check the stock and prices that would be sent in trial mode for a few days. If the numbers look right, go live.
Fetch orders
Once live, orders arrive in your system at regular intervals. In the first weeks, comparing each order with the marketplace panel avoids surprises.
Hepsiburada asks for a Merchant ID plus an integration username and password, N11 for an app key and secret, and Amazon for the seller and marketplace IDs plus authorisation details for the Selling Partner API. The logic is the same: get the key from the seller panel, enter it in the integration, test first, then go live.
Part 3 · Stock and price How does marketplace stock integration work?
The goal of stock integration is for the sellable quantity to show the same truth on every channel. When a product sells on your site, the marketplace quantity should drop; when goods arrive at the warehouse, it should rise everywhere. That needs a single source of stock that feeds every channel.
In a good stock integration, three settings make the difference:
- Channel buffer: A safety margin subtracted from the quantity sent to the channel. Sending 8 to a marketplace when you have 10 prevents going negative when two channels sell at the same time.
- Stopping sales: When you want to pull a product from a channel temporarily, sending 0 stock is safer than deleting the listing.
- Channel-specific price: On a high-commission channel it's natural for the price to differ from your site. Calculating the price rule from cost, target margin and commission prevents loss-making listings.
Part 4 · Product How do you set up marketplace integration in Heyşirket?
In Heyşirket, marketplace connections are part of the store module in your company panel and open in the Professional plan. Once the store is on, a Store group appears in the menu; marketplace work lives on the Marketplaces screen. The supported marketplaces are Trendyol, Hepsiburada, N11 and Amazon. There's also a summary on the marketplace integration page.
Setting up on the Store › Marketplaces screen
Enter the credentials
On the Marketplaces screen pick the channel and type the values from your seller panel into the Credentials section. The Where to find them in the seller panel? link takes you to the right page. Credentials are stored encrypted and never shown again.
Test the connection
Use Test connection to check the details. For Trendyol, Hepsiburada and Amazon you can also work in the marketplace's own sandbox with Use the channel's test environment.
Choose the mode
The Mode field has three options: Off, Trial (not sent) and Live. In trial mode stock and prices are calculated but not sent to the channel, and orders aren't imported.
Set stock and price options
Set the safety margin with Channel buffer, whether prices go too with Send price too, and how the channel price is rounded with Rounding.
Sync and fetch orders
Once live, changed stock and prices go to the channel at regular intervals; if you don't want to wait, press Sync now. Orders are also fetched regularly, and Fetch orders pulls them immediately.
The Delivery log section shows the result of each send; you queue records the channel rejected again with Retry failed. Products without a barcode or SKU are left out of stock sends and counted separately on screen.
When an order from a marketplace is recorded in your store, the stock of a stock-tracked product goes down and the new quantity is sent to the other channels too. Because the sale has already happened on the channel, stock doesn't go negative; it stops at zero. If the same channel order arrives a second time, no new record is created and the first order stands, which prevents duplicate orders when a connection drops and reconnects.
Products that don't yet have a listing on the marketplace can be sent as listings with Submit products. Before sending, the title, description, barcode (SKU on Amazon), at least one image, price, VAT, brand, category mapping and the channel's required attributes are checked; a product with gaps stays out of the batch and remains on screen with the reason.
Part 5 · Other channels Google and Meta feeds, and shipment tracking
Beyond marketplaces there are two more visibility channels. The Product feeds screen provides your products as a ready feed address for Google Merchant Center and the Meta catalogue (Facebook, Instagram). You add the address to the platform, and the platform reads your products from it. Products that aren't published or lack a price or image stay out of the feed; sold-out products aren't hidden, they're sent as out of stock.
The shipping side of an order is on the Shipment tracking screen. For Yurtiçi Kargo, Aras Kargo and MNG Kargo (DHL eCommerce), tracking can be set up through the carrier's own API. Here too there are three modes: Off, Trial (show only) and Live. In live mode the tracking result is written to the shipment and the order moves forward; in trial it's only shown. Shipments with other carriers are updated manually or from the marketplace.
Part 6 · Accounting From order to invoice and payout
Once an order arrives, the work moves to accounting. In Heyşirket, accounting is included in the Professional plan; an invoice draft is created from the order, and you check and issue the invoice yourself. The document type becomes e-Fatura or e-Arşiv depending on the buyer's status.
The payment the marketplace makes to you, the payout, is tracked on the Payouts screen. If your Trendyol connection is set up in accounting, invoices for the orders are marked as collected automatically when payments arrive; commission, shipping, service fee and withholding deductions appear on separate lines. If an order doesn't match, you link it to the invoice manually.
Details on linking channel products to your product records are in the product matching guide. If you're also thinking of selling on your own site, starting e-commerce covers the store side.
Part 7 · Cost Is free marketplace integration possible?
Marketplace APIs are open to sellers for free; the cost comes from the software that uses them. In Heyşirket, marketplace connections aren't sold as a separate integration product; they're part of the store in the Professional plan (699.99 TL/month or 6,999.90 TL/year, VAT included). The same plan includes accounting. The free Starter plan has no store or marketplace connections.
e-Fatura and e-Arşiv credits are separate from the plan and priced by your e-Document provider. The full plan comparison is on the Pricing page. Step-by-step help in the panel: Help › Store setup.
Before you start integrating
- Every product has a unique barcode or SKU.
- My product records have cost, VAT rate and brand filled in.
- There's one clear source of stock; I don't keep stock by hand anywhere else.
- I've set my channel buffer and channel price rule.
- I'll watch the channel in trial mode for the first week.
- I know how I'll share commission and payout records with my mali müşavir (certified accountant).
What is marketplace integration?
Marketplace integration is the automatic transfer of product, stock, price and order data between a seller's system and marketplaces such as Trendyol and Hepsiburada through an API. It removes manual updates and stock differences between channels.
Where do I find my Trendyol API details?
In the Trendyol seller panel, the integration information section under your account details shows the Supplier ID, API key and API secret. These three values are enough for the integration.
Which marketplaces does Heyşirket integrate with?
The Store › Marketplaces screen in the Heyşirket company panel sends stock and prices to Trendyol, Hepsiburada, N11 and Amazon, fetches orders and can submit product listings. It also provides product feeds for Google Merchant Center and the Meta catalogue.
Does anything go to the marketplace in trial mode?
No. In trial mode stock and prices are calculated and shown in the delivery log, but nothing is sent to the channel and orders aren't imported. You switch to Live once you've checked the numbers.
Is the invoice for a marketplace order issued automatically?
No. An invoice draft is created from the order, and you check and issue the invoice yourself. This prevents invoices being issued by mistake for cancelled orders.
Connect your marketplaces Enter the credentials, check the stock and prices that would be sent in trial mode, and go live when you're ready. Go to Marketplaces
Author: Heyşirket Editorial Team