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United States Postal Service (USPS)

ALL Merchants shipping with USPS must follow the updated guidelines which can be found at

Registration and Activation

To activate the US Postal Service as one of the shipping providers used by your store, follow the steps outlined below.
  • Register an account at the following address:
  • You will receive an e-mail from the USPS containing a User ID. Although the message might say that you need to use a test URL to test your account, according to our experience this is not needed (this is because it is already integrated within the USPS shipping API and is “ready to go”).
  • Simply contact the USPS at the address specified to have them switch your account to “production mode”.
Switch to Production Mode
Contact USPS at the address specified in the e-mail message that you received after registering and ask them to switch your account to production mode. Include the following information:
  • USPS User ID contained in the email you have received
  • You are using ProductCart, a 3rd party shopping cart tool that has been integrated and tested with the USPS Web Tools.

They then will move your account to the production servers as “confirmed”. Your store will NOT be able to obtain shipping rates from USPS until your account has been switched to production mode. You will then receive another email from USPS providing your USPS ID again and the “production URL”.
Activate USPS in ProductCart
At this point you can return to ProductCart and start the USPS configuration process. You will simply need to provide your User ID and the location of the server that your store will connect to. The server location is pre-filled on the page and you should not need to edit it. It is also shown below. Make sure the URL to the server is entered exactly as shown (sometimes users forget to add the "http://" at the beginning of the URL, for example).

USPS Shipping Settings
  • Service Selection \\Select which shipping services you wish to provide to your customers, among all the services that the USPS makes available to you. For each service, check the box next to the shipping service name to enable that option, then configure the following additional settings. These settings are shipping service-specific. For example, you may choose to make Priority Mail free for all orders that exceed $150.
    • Free Shipping
      Whether or not you wish to offer the selected service free to your customers when the order total exceeds a certain amount. If so, check the appropriate box and enter the order amount above which the selected service will become free.
    • Shipping & Handling
      Whether or not you wish to charge additional shipping and handling fees when customers select that particular shipping service. Enter the additional fee in the appropriate input field, then select whether you wish to display the fee as a separate shipping and handling charge, or rather to combine it with the shipping rate itself.
  • Packaging Type
    The next screen will ask you to select the packaging type used for the selected services. USPS allows customers to use special boxes that apply specifically to two of its services (Priority Mail and Express Mail). For these and all other services you may also use your own packaging: specify a default package size here.
  • Oversized Products
    When you add or modify a product, you can enable the Oversized option, which will have the following three consequences on shipping rates calculation:
    • The product will be flagged as Oversized (this may trigger extra shipping charges).
    • The product-specific package dimensions entered on the add/modify product page will replace the default package size mentioned above.
    • The product will be regarded as a separate package (e.g. if a customer purchases 3 units of the product, ProductCart will calculate rates for 3 separate packages).
  • Summary
    A summary page will provide a list of services that have so far been configured on the store, links to edit and/or remove them, and links to add new shipping options.

USPS Shipping Wizard

When USPS is active on your store, you will be able to use the USPS Shipping Wizard when shipping an order. The Wizard works exactly as those for the other shipping providers (or your custom shipping options) in terms of selecting the products that you would like to ship (and therefore support multiple shipments), etc.
Printing USPS Shipping Labels
ProductCart supports the printing of domestic shipping labels for the United States Postal Service. To activate this feature, you need to follow the steps outlined below. Note that:
  • You cannot print the actual postage from within ProductCart, but rather just the USPS shipping label. Postage can be obtained separately (e.g. through a scale and postage meter solution such as those by PitneyBowes,, Endicia, etc.).
  • You can only print labels for domestic shipments only
  • Print the label and the postage at the same time through the Endicia integration (see below)
  • The Endicia integration supports Express Mail International, so you can print labels for international shipments as well
Activating Label Printing
USPS does not turn on access to the Label APIs when you activate an online Web Tools account. To print USPS labels, you need to do the following:
  1. Email USPS at and request access to the Labels API. Specify the following three APIs by name:
    • Signature Confirmation
    • Delivery Confirmation
    • Express Mail Labels.
  2. USPS will turn on test mode and the you should be able to print 'SAMPLE' labels.
  3. Once your have generated a 'SAMPLE' label, you can request to be put into Production Mode for the Express Mail Labels API. Send the request via e-mail to the same address mentioned above. USPS might ask you if you are going to be customizing or changing the labels: respond that the default label is going to be used with no customizations.
  4. There is a switch in the Control Panel to go from Test to Production mode.
Printing the Label
  • ​Load the order details page for the order that you wish to ship
  • Click on the Shipping Center tab: you will see the USPS Shipping Wizard section at the bottom of the page.
Exporting and Printing Elsewhere
If you prefer printing your labels using another system (e.g. USPS Shipping Assistant, Endicia, etc.), you can use the “Export Addresses to USPS Shipping Assistant” feature to export shipping addresses. This feature, which is located under Reports/Custom Data Exports, formats a file that will import directly into the “USPS Shipping Assistant” software provided by USPS.

USPS Shipping Assistant is a free program provided by USPS that allows you to print labels with postage. For more information, visit:

The file exported by ProductCart is in a comma delimited format that is compatible with the USPS Shipping Assistant software. However, this feature (or the file itself), can be easily modified so that it meets the requirements of other import tools. Note that the only information exported from ProductCart in this file is the shipping profile and not product ordered information.
  • Make sure that pcadmin/USPSLabels folder exists
  • Make sure that the folder has read/write permissions so that labels can be written to it.​