Shopify Amazon integration for listings, orders, inventory and fulfillment

A Shopify Amazon integration lists your Shopify products on Amazon, imports Amazon orders into Shopify, and keeps inventory in sync so you don't oversell. Shopify's own Marketplace Connect app and several third-party apps cover this for most sellers. Amazon also offers apps for Buy with Prime and for Multi-Channel Fulfillment (MCF) from FBA stock. Custom integrations make sense for large catalogs with marketplace-specific rules, or when Amazon data has to flow into an ERP or accounting system in a specific shape.

What flows between Shopify and Amazon

• Listings: products, variants, images, attributes, prices. Amazon's catalog works differently from Shopify's. Products match to existing ASINs or create new ones, each Amazon product type has required attributes, and variation families have strict rules.
• Orders: Amazon orders imported into Shopify for fulfillment and reporting, with the marketplace as the sales channel.
• Inventory: shared stock across channels, with a buffer per channel if you want one.
• Fulfillment: merchant-fulfilled orders ship from your locations and tracking goes back to Amazon. FBA orders are fulfilled by Amazon.
• Settlements and fees: Amazon pays out on its own schedule, net of referral fees, FBA fees, refunds and adjustments.

Off-the-shelf options

• Shopify Marketplace Connect, Shopify's own app, which supports Amazon (as well as eBay, and Walmart and Target Plus in the US).
• Amazon's apps: Buy with Prime (Prime checkout on your Shopify store, fulfilled by Amazon) and Amazon MCF (ship Shopify orders from FBA inventory).
• Third-party multichannel apps listing on several marketplaces at once.
• Inventory or order management systems that connect to both, if you already run one.

Where Amazon connectors break

• Catalog mapping. Shopify options such as Size and Colour don't always map to the variation theme Amazon expects for your product type. Required attributes differ by category.
• Selective and marketplace-specific data. Different titles, bullet points, prices or bundles for Amazon than on your own site, per Amazon marketplace.
• Multi-location inventory with FBA. Stock in FBA, at your warehouse and at a 3PL, with different rules per channel.
• Order edits and cancellations on the Amazon side after import.
• Accounting. Imported Amazon orders show as sales in Shopify, but the money arrives through Amazon settlements. Without a separate clearing account, revenue is double-counted or doesn't reconcile.
• Error feedback. Listing errors from Amazon come back asynchronously and are easy to miss.

How a custom Shopify Amazon integration works

1. Amazon's Selling Partner API (SP-API) on the Amazon side, authorized for your seller account. It covers listings, orders, inventory, reports and notifications.
2. Listings: the app reads products from Shopify with the GraphQL Admin API, including metafields that hold Amazon-specific attributes (product type, bullet points, browse node and so on), and submits them per marketplace. Listing issues come back from Amazon and are shown per SKU.
3. Orders: new Amazon orders arrive through SP-API notifications or polling and are created in Shopify, tagged with the channel and the Amazon order ID. The Amazon order ID is the idempotency key.
4. Inventory: Shopify stays the source of truth for merchant-fulfilled stock and pushes available quantities to Amazon, with any buffer applied. FBA inventory is read from Amazon and written to an FBA location in Shopify.
5. Settlements: Amazon settlement reports are parsed and posted to accounting separately from Shopify payouts.
6. Monitoring: listing errors, failed order imports and stock mismatches between channels are shown in one list.

Worked example: inventory with buffers and FBA

Say a SKU has 40 units at your warehouse and 100 units at Amazon fulfillment centers:

• Shopify shows 40 available at the warehouse location and 100 at an FBA location. Shopify orders are fulfilled from the warehouse, or from FBA through MCF if you set it up that way.
• Amazon merchant-fulfilled offer: the integration pushes warehouse stock minus a buffer, say 40 − 5 = 35, so a burst of Amazon orders can't oversell before the next sync.
• Amazon FBA offer: Amazon manages the 100 units itself. The integration only reads them back into Shopify.
• When a Shopify order ships from the warehouse, the warehouse drops to 39, and the merchant-fulfilled quantity on Amazon is updated to 34.

The buffer, the locations included and whether FBA stock can fulfil Shopify orders are configuration, not code, so operations staff can change them during peaks.

Common failure modes

• Variation family errors. A listing is rejected because the child variations don't match the variation theme. Show the Amazon error per SKU, and keep the Amazon attributes in metafields so they can be fixed in Shopify.
• Price errors. Amazon rejects prices it considers outside a reasonable range for the product. Price updates need their own error handling.
• Duplicate orders. An order imported twice after a timeout. The Amazon order ID as idempotency key prevents this.
• Cancelled after import. Amazon cancels an order that's already in your warehouse queue. The integration must cancel it in Shopify and alert the warehouse.
• Token expiry. SP-API authorization must be refreshed. Alert before it breaks, not after.

Testing

Amazon's SP-API offers a sandbox for testing calls. Combine it with a Shopify development store for order import and inventory logic, then test with a handful of live SKUs before switching on the whole catalog.

Decision checklist

• Which Amazon marketplaces do you sell on, or want to?
• FBA, merchant-fulfilled, or both? Do you want MCF for Shopify orders?
• How many SKUs, and how many need Amazon-specific content?
• Is Shopify the hub for orders and inventory, or is an ERP?
• How will Amazon settlements be recorded in accounting?