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Connecting your store to Amazon: integrator or your own API
Daniel Pawłowski · Amazonway · · approx. 7 min read
Your online store and Amazon need to know three things about each other: how much stock you have, what you sell it for and what has already been ordered. Without an integration someone re-keys it by hand, and the first product sold twice ends in a cancellation and a worse account score. This piece compares three ways of connecting a store to Amazon and sets out what each costs and when it makes sense.
For most brands with their own store the cheapest route is a ready-made integration platform, which at typical volumes costs from nothing to a few hundred euros a month. Your own integration via Amazon's API makes sense for unusual processes, very high volume or an ERP that no integrator supports. Either way, the biggest cost is not the subscription but bringing your product data up to Amazon's requirements.
Sources checked: 30 September 2026. Integrator prices come from their public price lists on that date and change independently of us.
What has to stay in sync
| Data | Direction | What happens when it drifts |
|---|---|---|
| Stock levels | from your system to Amazon | selling goods you do not have, cancellations and worse account metrics |
| Prices | from your system to Amazon | selling below margin, or an offer dearer than in your own store |
| Orders | from Amazon to your system | an order nobody packed in time |
| Shipping status and tracking | from your system to Amazon | late shipment confirmations, which count against your account |
| Listings and product data | from your system to Amazon | listings rejected or invisible in search |
If you use FBA, one difference matters: you do not sync stock for FBA offers. The goods sit in Amazon's warehouse and Amazon knows how many there are. A common setup mistake is pushing your own warehouse stock onto FBA offers, which at best does nothing and at worst muddles the reports.
Three ways to connect
1. By hand in Seller Central
You add listings through the form or an upload template and handle orders in the panel. It works with a dozen products and a few orders a day. It stops working once the same stock is sold in your store and on several marketplaces at once.
2. An integration platform
One tool connects your store, marketplaces, carriers and invoicing. As a reference point from Central Europe, where we work most: Base (formerly BaseLinker) publishes a free plan up to 100 orders a month and a Business plan at 279 PLN net a month for 1,000 orders (Base pricing), and Apilo publishes plans from 39 to 999 PLN net a month (Apilo pricing). This is not a ranking: the right tool depends on your store, ERP and carriers.
3. Your own integration via Amazon's API
Amazon's Selling Partner API lets you process orders and shipments automatically, create listings, sync inventory across Amazon stores, update prices, and retrieve financial and tax data and invoices (Amazon documentation). It is a software project: developer registration, authentication, rate limits and maintenance every time Amazon changes something.
What an Amazon integration costs
- The integrator subscription: see above, from nothing to a few hundred euros a month at typical volumes.
- Implementation and data mapping: mapping your categories and fields to Amazon product types, variations and GTINs. The cost depends entirely on the state of your data, so it cannot honestly be quoted without seeing it.
- Maintenance: fixes after Amazon changes its requirements and for new products. With your own API integration it is a standing developer cost; with an integrator it is largely carried by the tool's vendor.
We cost the whole of entering a new channel, not just integration, in our piece on what another marketplace really costs.
The bottleneck is product data, not technology
An integration moves data; it does not fix it. Amazon requires different fields for each product type, GTINs and consistent variations. If your store keeps the description in one text field and the specifications in the images, no integrator will build a good listing from it. What to check before you connect is set out in our piece on Amazon product data requirements.
The trap: integrations built before 2025
Since 31 July 2025 Amazon no longer accepts listings, prices, inventory, variation relationships or images through the API in the legacy XML and flat-file feed formats. They were replaced by the Listings Items API and the JSON listings feed (Amazon changelog). If you run a custom integration from a few years back, or a little-known store plug-in, check that it has been rewritten. The symptom of a missed migration is simple: listings stopped updating and nobody got an error message.
Six questions before you choose an integrator
- Does it support your store, ERP, carriers and invoicing all at once?
- Does it list on Amazon through the current API, with product types and variations?
- Does it distinguish FBA offers from self-shipped ones?
- Does it handle several European Amazon stores from one account?
- Can you set a stock buffer so the last units are not sold on several channels at once?
- What will it cost at the volume you plan for next year, not just today?
How Amazonway helps
We configure and maintain integrations between your store and Amazon, Allegro and other marketplaces, and above all we clean up the product data without which an integration achieves nothing. The scope is on our integrations and automation page. We do not sell any of the integration tools, so we fit the tool to your process rather than the other way round.
Talk to us about connecting your store to Amazon →
FAQ: connecting your store to Amazon
Do I need a developer to connect my store to Amazon?
With a ready-made integrator, usually not: configuration happens in its panel. You need a developer for your own integration via the Selling Partner API or for an unusual system that integrators do not support.
Should I sync stock for FBA offers?
No. FBA offer quantities come from the stock in Amazon's warehouse. You sync stock only for offers shipped from your own warehouse.
My integration stopped updating listings. Why?
One common cause is a missed API migration. Since 31 July 2025 Amazon no longer accepts listings, prices and inventory through the API in the legacy XML and flat-file formats.
Integrator or my own API integration?
An integrator if it supports your store, ERP and carriers. Your own API integration when you have an unusual process, very high volume or a system with no ready-made connector, and are prepared for a standing maintenance cost.
Sources
- Amazon, What is the Selling Partner API
- Amazon, removal of Feeds API support for XML and flat-file listings feeds
- Base pricing and Apilo pricing (as of 30 September 2026)