# Marketplace integration: syncing products, stock and orders with Trendyol, Hepsiburada and Amazon > Marketplace integration sends product, price and stock data from your own system to marketplaces such as Trendyol, Hepsiburada and Amazon, and pulls their orders back into one place. The foundation is a single stock source: stock lives in one system and every channel reads from it. An off-the-shelf connector suits standard needs; custom integration fits when you have your own business rules or need a deep link to your own software. - URL: https://radkod.com/en/blog/marketplace-integration - Publisher: RadKod - Published: 2026-09-09 ## In short - Marketplace integration moves products, prices, stock, orders, shipping and invoices between channels without manual entry. - Keep stock in one system. The website and every marketplace read from it, never from each other. - An off-the-shelf connector works for standard catalogues. Custom integration fits your own rules and systems. - Most sync problems come from delays, rate limits and mapping errors, and are handled with logging and alerts. ## What is marketplace integration? Marketplace integration is a software link that keeps your products and orders in sync between your own system and marketplaces such as Trendyol, Hepsiburada and Amazon. You enter a product once and it is sent to each marketplace. When stock changes, every channel updates. Marketplace orders land in your own panel. Without it, all of this is manual. Forget to lower stock on one channel after a sale and you sell something you do not have. You cancel the order, and the marketplace may count that against your seller rating. The link is built through each marketplace's seller [API](/en/glossary/api). Trendyol and Hepsiburada offer their own seller integration APIs, and Amazon's is the Selling Partner API. Each has different rules, field names and limits. Much of the work is bringing those differences into one model. ## What does marketplace integration automate? Marketplace integration automates six flows: products, prices, stock, orders, shipping and invoices. You do not need all of them at once. Most businesses start with stock and orders. ## The six flows an integration carries - **Products**: Titles, descriptions, images, barcodes, variants and category attributes, mapped to each marketplace's category tree. - **Prices**: A separate rule per channel, adding commission and shipping cost to your base price. - **Stock**: When stock changes at the source, every channel gets the new number. - **Orders**: New marketplace orders flow into your panel, CRM or accounting software, and status changes flow back. - **Shipping**: Labels, tracking numbers and delivery status are sent to the marketplace. - **Invoices**: The invoice issued for the order is attached to it on the marketplace. ## What is the single stock source rule? The single stock source rule means stock is kept in exactly one system and every sales channel reads its numbers from there. That source can be your online shop, warehouse software or accounting and [ERP](/en/glossary/erp) system. Which one does not matter. That there is only one does. The mistake we see most: the website pushes stock to Trendyol, Trendyol sales are written back to the website, and the warehouse team updates a spreadsheet on the side. Three places try to correct each other and nobody knows which number is right. With one source, a sale from any channel lowers the source, and the source sends the new number everywhere. Because sync takes seconds to minutes, many sellers also send a slightly lower number for items that are nearly sold out. ## How are products sent to a marketplace? Products are sent by mapping your product data to the marketplace's categories and required attributes. A T-shirt may need size, colour and fabric. A phone case may need compatible models. The slow parts are barcodes, variants, image rules and approval: some marketplaces review new listings before they go live. Some APIs also queue bulk uploads and report results later, so the integration must check every batch and show you what failed. ## How do orders, shipping and invoices flow? Orders are pulled from the marketplace into your system, and status updates go back as you pack and ship. Many integrations poll on a schedule. Where the marketplace supports it, a [webhook](/en/glossary/webhook) announces new orders instantly, and a scheduled check catches anything missed. Cancellations and returns belong in the same flow from day one. For sales in Turkey, the invoice is an e-invoice or e-archive invoice issued by your invoicing system and then linked to the marketplace order. That is the job of the invoicing integration, which we cover in [e-invoice integration in Turkey](/en/blog/e-invoice-integration-turkey). Ask your accountant which document applies to which sale. ## Off-the-shelf connector or custom integration? An off-the-shelf connector is enough for a few channels and a standard catalogue; custom integration is better when you need your own rules and a deep link to your own systems. They are not always rivals. Sometimes the connector handles the marketplaces and we build the link between its API and your software. **Off-the-shelf connector versus custom integration** | | Off-the-shelf connector | Custom integration | | --- | --- | --- | | Time to start | Short; sign up and configure | Longer; built to scope | | Cost model | Monthly or per-order fee | One-off build plus optional upkeep | | Business rules | Limited to available settings | Your pricing, stock and warehouse rules | | Link to your systems | Only the platforms they support | Directly to your site, CRM and ERP | | Adding a marketplace | Usually ready | Each one is separate work | | Data and code ownership | With the provider | Yours, in your own repository | ## Why do sync problems happen? Sync problems mostly come from delays, rate limits, mapping errors and requests that fail silently. Marketplaces cap how many requests they accept in a given window, so we send changed items in ordered batches instead of every product one by one. Orders are stored by their marketplace ID so a retried request never creates a duplicate. Every failure is logged and retried, and repeated failures send you an alert. A daily reconciliation report compares stock on each channel with the source and lists the differences. Marketplaces also change their APIs and categories, and keeping up is part of maintenance. ## What drives the cost? The cost depends on the number of marketplaces, the flows you automate, the size of your catalogue and how clean your product data already is. We send a one-page quote that names the channels and flows and says when the work counts as done: listings live, stock and orders verified with real orders, reconciliation running. Bugs found within 30 days of handover are fixed free. We often handle the accounting side in the same project. See [accounting and ERP integration](/en/blog/accounting-erp-integration). For the wider platform choice, read [e-commerce platform or custom build](/en/blog/ecommerce-platform-or-custom). This work sits under our [integrations](/en/services/integrations) service, and your own shop under [e-commerce](/en/services/e-commerce). ## Frequently asked questions ### Do I need my own online shop? No. The stock source can be warehouse software, an accounting system or a simple admin panel. What matters is that there is only one. ### Can we connect Trendyol, Hepsiburada and Amazon at once? Yes, but each has its own rules. We usually start with one and add the others once the flow is stable. ### How fast does stock sync? From seconds to a few minutes, depending on the marketplace API and its rate limits. That is why we suggest a safety margin for low-stock items. ### What happens if I oversell? You have to cancel the order, and marketplaces may count cancellations against your seller performance. One stock source and a safety margin reduce the risk. ### Can I move from a connector to a custom integration later? Yes. It is easier if product mappings and order history can be exported. We switch channel by channel. ### Who issues the invoice for marketplace orders? You do, as the seller. The integration creates it in your invoicing system and attaches it to the order. Ask your accountant about the document type. ### Will the integration break if a marketplace changes its API? It can. Marketplaces usually announce changes in advance, and adapting to them is part of maintenance. ## Sources - [Selling Partner API Documentation](https://developer-docs.amazon.com/sp-api/), Amazon - [e-Belge](https://ebelge.gib.gov.tr/), Revenue Administration of Türkiye (GİB) **Manage your stock from one place** [Get a quote](https://radkod.com/en/get-a-quote)