This article explains Loop's Amazon MCF (Multi-Channel Fulfillment) integration, which connects Loop with Amazon's fulfillment network through the Amazon SP-API. With this Amazon returns integration, when a shopper submits a return in Loop, Amazon automatically generates a return shipping label that the shopper uses to send the item back to an Amazon fulfillment center — and the return's status and item condition sync back into Loop. Use this guide to understand how the integration works and how to set it up.

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Amazon Multi-Channel Fulfillment (MCF) is Amazon's fulfillment service that lets merchants use Amazon's warehouse network to fulfill orders placed outside of Amazon.com.

Loop's Amazon MCF integration connects Loop Returns with Amazon's fulfillment network and does two things:

• Return label generation — when a shopper submits a return in Loop, Amazon automatically generates a return shipping label. The shopper uses the label to send the item back to an Amazon fulfillment center.

• Return data syncing — the return is created in Amazon, and as Amazon receives and inspects the item, its condition and grading sync back into Loop. Discrepancies (damaged, defective, or missing items) are flagged for review.

This integration requires an Amazon Seller account with Multi-Channel Fulfillment enabled and access to the Amazon Selling Partner API (SP-API).

1. A shopper submits a return in Loop.

2. Loop sends a return label request to Amazon MCF, and Amazon creates a return authorization and generates a shipping label.

3. The label is delivered to the shopper through Loop.

4. The shopper ships the item to an Amazon fulfillment center.

5. As Amazon receives and processes the item, its condition and grading data sync back into Loop.

6. If there are no discrepancies, Loop processes the return outcome (refund, exchange, or store credit) as normal. If Amazon reports a discrepancy (damaged, defective, or missing), the return is flagged in Loop's Needs Review queue and pauses for your team to review. For exchanges with auto-process enabled, discrepant items are automatically removed.

Note: Label generation typically completes within a minute. The integration automatically waits for Amazon to finish generating the label before delivering it to the shopper — no action is needed on your end.

From Amazon Seller Central:

• Login to Amazon via OAuth2

• Your Marketplace

• Return Service ID — a separate credential provided by Amazon that authorizes reverse logistics. Contact your Amazon account manager if you don't have this.

From Loop:

• A Loop API key — generate it in the Loop admin under Returns management > Tools & integrations > Developer tools. Required scopes: Return, Developer Tools, Destinations (read), Labels, and Label Generation Requests.

• Enable Enable Third Party Labels under Shop Settings in the Loop admin.

1. Contact the Loop team to receive your onboarding link for the Amazon MCF integration.

2. Open the link, navigate to the Credentials tab, and complete the Amazon authorization step as well as providing the Return Service ID.

3. Enter your Loop API key.

4. (Optional) Configure Return Reason Mapping to map your Loop return reasons to Amazon's return reason codes.

5. Begin testing with a live return.

Tip: If no mapping is configured for a return reason, Amazon's default reason code is used — so you can go live first and refine your reason mapping later.

After the integration is live, you'll see its effects in two places in the Loop admin:

• Return timeline — status updates synced back from Amazon appear on each return record.

• Needs Review queue — returns where Amazon reported a damaged, defective, or missing item are flagged here for your team to manually process or dismiss.

To check if this feature is included in your plan, please review the Pricing page on Loop's website.

If you want to add this feature, please contact your Merchant Success Manager to amend your account.

What is the Return Service ID?
The Return Service ID is a credential that authorizes your Amazon account to use Amazon's reverse logistics service. It is separate from your standard SP-API credentials. If you don't have one, contact your Amazon account manager.

Which Amazon marketplaces are supported?
The United States. Return label generation is currently US-only, so the integration is limited to the US for now.

How long does label generation take?
Label generation typically completes within a minute. The integration automatically waits for Amazon to finish generating the label before delivering it to the shopper — no action is needed on your end.

Why is my return sitting in the Needs Review queue?
This is expected when Amazon reports an item as damaged, defective, or missing. Open the return in the Loop admin to process or dismiss the discrepancy. For exchanges with auto-process enabled, discrepant items are removed automatically.

Can I customize which return reasons map to Amazon's reason codes?
Yes — configure a return reason mapping after setup. If no mapping is configured for a reason, Amazon's default reason code is used.

Who supports this integration?
If you run into any issues during setup or testing, please reach out to support@loopreturns.com. We're here to help.

Please reach out to support@loopreturns.com with any additional questions.