Integration With USPS Merchandise Return Service

ReturnGO integrates with USPS to help you manage your return shipping. 

USPS Merchandise Return Service allows authorized permit holders to pay postage and extra service fees so that items can be returned by customers using merchant-provided pre-paid labels at no charge to the customers.


The ReturnGO-USPS MRS Integration supports:

  • Pay-on-scan return labels
  • Live tracking status updates
    • Reach out to ReturnGO Support through chat or email to sign up for this service. 
  • QR codes
    • Enabled on demand. Reach out to ReturnGO Support through chat or email to sign up for this service. 
Return Labels Return Tracking QR Codes Auto Select Cheapest International Shipping
See a full feature comparison with other shipping carriers.


To link your USPS MRS account to ReturnGO, you will need: 

USPS MRS Merchant Account Code 

  • The Merchant Account Code is a 32-character alphanumeric code of your USPS MRS account. It is assigned when you get onboarded by your USPS Administrator. If you do not have one yet, send a request for your Merchant Account Code to


  • The Mailer ID (MID) is a 6 or 9-digit code associated with the Merchant Account Code. It is sent along with the Merchant Account Code
  • Return addresses are set in USPS - each mailer ID is related to a specific return address.

Note: Make sure to ask MRS Support for the Merchant Account Code

Linking Your USPS MRS Account to ReturnGO 

To link your USPS MRS account with ReturnGO: 

  1. Go to Integration > Products & Services
  3. Choose USPS Merchandise Return Service from the drop-down list. 
  4. Click on the green check mark.

Shipping integration steps-png

5. Enter your credentials. 
6. Click CONNECT. 

Adding the Integration to a Return Method

Once you've connected the integration, you'll need to add it to a return method:

  1. Go to Return Methods
  3. Click ADD RETURN METHOD or select a return method to edit.

Shipping integrations steps 1-png-1

4. Go to the Shipping Label Settings section. 
5. Set Connection to USPS. 
6. Select a service level.

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7. Verify your return address. 

8. Click on the save icon. 

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Note: The shipping instructions for USPS return shipments are not editable, and contain the content required by USPS.

Reach out to ReturnGO support to register for live tracking status updates. This may take 1-2 business days to complete. 

Troubleshooting the Integration

Many of the issues encountered related to integration can be identified during setup or label generation. 

Here are a few things you can check to try and fix such issues: 

Setup Issues

Make sure your API credentials are accurate. 

  • There should be no extra spaces before or after each API entry. 
  • Make sure you are using live or production API credentials, and not dev or test APIs. 
  • Try to re-generate a new API key and reconnect. 
  • If a carrier or service level is not available, contact your shipping service support team to verify which return services are available. 

Note: Some carriers support forward deliveries only, returns only, or both.

Label Creation Issues 

Verify your Return Address

  • Some carriers may not recognize special characters, which might cause issues when generating labels. 
  • Remove special characters and unnecessary spaces in your return address. 
    • For example: 
      • If your store name is “John & Jane Store”, change it to “John and Jane Store”. 
      • If your store phone number has “+” signs or “( )”, remove them. 

Verify the Customer's Address 

  • ReturnGO takes the customer's address when the request is submitted. 
  • If there are corrections to the customer’s address, reject and resubmit the return request. 

Verify the Item Weight 

  • If the total weight of the items being returned exceeds the service level’s weight limit, then the carrier will reject the label request. 

Verify if you can Generate a Return Label for the Order Directly in the Shipping Platform

  • If your shipping service platform cannot generate the label, then it will also fail in ReturnGO. 

USPS MRS-Related Issues 

For USPS MRS-related issues, please contact USPS MRS Support at

Other Issues  

For any other issues, feel free to contact ReturnGO Support through chat or email.