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United States Postal Service (USPS)

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
    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 version 3.1 and above support 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
  • With ProductCart v4.1 and above you can 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. E-mail USPS at and request access to the Labels API. Specify the following three APIs by name:
    1. Signature Confirmation
    2. Delivery Confirmation
    3. 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. USPS should now confirm that the label APIs are now in Production mode.
  5. Once you have confirmation from USPS that you are in “Production Mode”, there is a variable that allows you to switch the USPS Label printing feature from “Test” mode (sample labels) to “Production” mode (real labels) in ProductCart.
    1. ProductCart v3.51 and above: there is a switch in the Control Panel to go from Test to Production mode.
    2. Earlier versions: there is a hard-coded variable located in the file “USPS_ManageShipmentsRequest.asp” in the “pcadmin” folder (which has likely been renamed in your store). To change this variable, do the following:
      1. Download the file “USPS_ManageShipmentsRequest.asp” via FTP
      2. Open it in Notepad or your favorite HTML editor
      3. Locate the following code
        dim intSampleLabelsOnly

        … and change:


        … to:


      4. Save the file and upload it back to the Web server

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.

Integration with Endicia

ProductCart is now integrated with Endicia

Overview and Cost

New in ProductCart v4.1 is the integration with Endicia, which allows you to print USPS shipping labels that include postage. There is a cost associated with this service. Please note the following:

  • The price of the service is $15.95/month
  • This cost represents the cost of using the Endicia system through ProductCart. It does not include any postage, but rather only the Endicia service itself. You will purchase postage separately (more on this below).
  • There is no time commitment. You may cancel your subscription to the Endicia service at any time.
  • There is no fee for the first 30 days. The first charge will be at the end of the 2nd month after you sign up. So if you activate Endicia in ProductCart and then cancel your Endicia account within the first 30 days, there is no charge.

For technical reasons, you cannot use an existing Endicia account with the ProductCart integration with Endicia. If you are a current Endicia user, you will still need to sign up for a new account through the ProductCart Control Panel. Please contact Endicia if you have more questions on this requirement… it is outside of our control.

What it does

The integration between Endicia and ProductCart allows you to handle USPS shipments in a more efficient way as you are able to print shipping labels that include postage, unlike when using the USPS Shipping Wizard mentioned above, which prints labels that do not include postage.

Signing up

The first step is to sign-up for an Endicia account. You can do this right through the ProductCart Control Panel. Make sure you write down the passphrase and challenge question/answer because you will need them later. IMPORTANT NOTES Re: the PASSPHRASE: Choose a Passphrase NO LONGER than 20 characters. Do NOT use and “special” characters in your Pass Phrase (e.g. #, $, %) or you will not be able to request a postage refund through the API!

  • SSL
    The sign-up form must be loaded on a secure connection. That is: you must have an SSL certificate installed on your Web site and must load the ProductCart Control Panel using the HTTPS protocol. This is required because you will be entering credit card information on the form. If you are currently connected to the ProductCart Control Panel using HTTP, change the URL so that it uses HTTPS.
  • Credit Card information
    The sign-up form asks for credit card information:
    • To purchase the Endicia service. Note that you will not be charged until the second month (as mentioned above)
    • To purchase postage. Your credit card information will be held securely by Endicia, which will allow you to quickly add postage to your account with just one click, right from your ProductCart Control Panel

Activating your account

When you submit the form, Endicia will receive your information and automatically create an account for your. When your Endicia account is ready (this normally happens immediately), you will receive a confirmation e-mail at the e-mail address you provided. The e-mail will include your Endicia account number.

When you receive that message, copy the account number to your clipboard and go back to the ProductCart page where you manage the Endicia integration (Shipping > Add/View Shipping Services > USPS and Endicia > Manage Endicia Account). Enter the following information:

  • Your Endicia account number
  • Your pass phrase
  • A new pass phrase
  • Confirm the new pass phrase

Submit the form. This will confirm with Endicia that the account number that was created for you is associated with your ProductCart-powered store. You will receive a success message when the account has been activated.

Please Note: we have had reports that the Endicia integration does not appear to work with XML v6. If you are having problems with the integration between ProductCart and Endicia, change the XML parser used by your store. You can do so using the Troubleshooting Utility under the Help menu.

Add postage

You can now add postage to your Endicia account. The minimum amount is $10. As you can see, this can be done in just one click, right from your ProductCart Control Panel.

When you purchase postage, you will receive a confirmation message from Endicia ( indicating the amount purchased, date and time of purchase, a confirmation number, and your current postage balance.

You can also view your current postage balance in the ProductCart Control Panel in the Endicia account management area.

Additional settings

Once you have enabled Endicia, you will manage your account from the ProductCart Control Panel under: Shipping > Add/View Shipping Services > USPS and Endicia > Manage Endicia Account

  • Using “Live Mode”: use this setting when you are ready to begin printing USPS labels and postage.
  • Using “Test Mode”: use this setting to test the labels. You will NOT be able to ship items when the label has been created in Test Mode.
  • Log Transactions between your store and the Endicia Postage Label Server. If you check this box, ProductCart will keep a XML log of each exchange with Endicia. This can be useful for troubleshooting an issue related to the printing of a particular postage label, however if you check this box… you should make sure to enter a low number in the box to 'Automatically clear logs older than _ days' (such as 3-5 days), so that your log files do not grow too big.
  • Auto refill your account. You can choose to have your Endicia account replenished when the original credit card balance is used up and drops below a certain threshold. To do so, check the box and enter the dollar amounts in each box for the threshold and the replenishment amount.
  • Transaction Logs. Click the link to open a page that details all of your Transaction Logs that haven't been cleared based on the above variable.

Mail Class - Package Type Matrix

The following table shows valid combinations of package types and mail classes, grouped by label type.

Endicia Shipping Wizard

When you are ready to Ship an Order and print the USPS Postage Label, go to the Order Details page and then click on the “Shipping Center” tab where you will see a section labeled “U.S.P.S. Shipping Labels”. click on the 'Start Shipping Wizard' button to see the products that are available to be shipped, Check the box(es) next to the product(s) that you will be including in this shipment only, and click 'Continue'.

You will now be on the “USPS Shipping - Endicia Postage Services Wizard” page, which has been consolidated into 5 tabs for your convenience.

Endicia Postage Label

Account Balance

Here you will see your current Account Balance and also have the opportunity to refill (replenish) your account balance if desired. At the bottom of the page, you will see a button to 'Calculate Postage Price', however before you do that, we recommend that you review the selections and data on the other tabs to make sure it is correct!

Label Settings

This tab contains the 'Mail Class' selected by the customer during checkout (e.g. Parcel Post, Priority Mail, etc.), however you can change it to another service type as long as it's supported for this shipment. If USPS services weren't selected during checkout, the Mail Class defaults to the first radio button, which is Express Mail.

- Label Attributes: This determines the file format for the postage label. The GIF format is pre selected however JPEG, PNG and PDF are also supported.

Ship Settings

On this tab you can specify whether to 'Flag this package as shipped' once the postage label has been printed, as well as enter comments that are in addition to the verbiage that is already included in the 'Order Shipped' e-mail that gets sent to the customer.

- Ship Date dropdown allows you to specify the actual Ship Date, up to 5 days in advance.

Ship From/Recipient

This tab is where you will review the 'Ship From' and 'Ship To' address details prior to printing the postage label. This information is dynamically populated based on the merchant's 'Shipping Address' and the one specified by the customer during checkout, so you should not have to edit this page! An exception might be if the customer's address doesn't “pass” Endicia's address validator, in which case you will need to make the necessary correction, or contact the customer for an alternate address. DO NOT contact ProductCart if you receieve a message from Endicia that the address is not acceptable, as there is nothing we can do on our end to resolve this. The message is coming directly from Endicia.

Package Information

This tab is an important one! Here, you can review the Package Value, which is based on the Order Total, but can be edited if necessary. NOTE: this value is required for international shipments. The Package Description field is populated with the Order ID, but can also be edited.

  • Package Weight is based on the aggregate weight of the contents of this shipment, but can be adjusted by the merchant if necessary.
  • Package Type will default to the most common one for the Mail Class, but can be changed by the merchant to any other one that is compatible. The Package Dimensions are based on the default package size under your Shipping Settings, but can also be edited.
  • Package Reference Number. By default, the Customer ID will be used as a 'cross-reference' number, but you can change this prior to Calculating Postage.
  • Additional Services - Insured Mail. Insuring the package is not required, however if you choose to insure the package, your only option is to use Endicia's Insurance (i.e. the USPS Insurance is not avaialable, but Endicia's is actually less expensive and more comprehensive anyway). it is important to understand that the Insurance Amount is NOT included with the postage, but billed to your account at the end of each month. For more information on Endicia's insurance rates, please go to:


If you make a mistake and therefore decide not to use a label that you have created with the USPS Endicia Shipping Wizard, you can request a refund directly from the ProductCart Control Panel:

  • Load the order details page for the order for which the shipment label is incorrect (or no longer needed)
  • Go to the Product Details tab
  • Locate the shipment details section lower on the page
  • Click on the Refund link next to the shipment for which you would like to receive a refund

The refund request will be processed and you will receive an e-mail confirmation directly from Endicia in a few days. If the refund is approved, the postage associated with that shipment will be automatically credited back to your Endicia postage account.

Stealth Mode

If you want to 'hide' the actual postage amount on the shipping/postage label, you can do this be making a small change in the file:


Open it in Notepad or another editor and look for the following line:

tmpXMLOrg=tmpXMLOrg & "<Stealth>FALSE</Stealth>"

… Change it to:

tmpXMLOrg=tmpXMLOrg & "<Stealth>TRUE</Stealth>"

Please note that their API states the following about this mode:

Stealth cannot be used with COD, USPS Insurance, Registered Mail, Automation rate, LabelSize of EnvelopeSize10 and Card shape mailpieces. For Standard Mail, Stealth is turned on.

QR Code
QR Code United States Postal Service (USPS) (generated for current page)