The first step in configuring real-time rates for USPS services is to sign up for a USPS Web Tools account. You can sign up for an account at: will then email you an API username, which is needed to configure the CoreCommerce admin panel.

Additionally, USPS requires you to contact them and request your account to be moved to the production server. You can call their internet customer care center at 1-800-344-7779 or send them an email at Rate quotes will not show up on the front end until you have called the internet customer care center and have your account moved to the production server.

Once you have the API username from USPS, the next step is to configure the CoreCommerce admin panel:

  • Click Settings -->Shipping Settings
  • Click on "Configure Real-Time Carriers."
  • Make sure that USPS has a green check mark above the USPS logo and that you have set Do you use real-time shipping rates, order tracking, or label printing?  >  to YES.
  • Save and Continue


  • On the next screen, enter your API username in the "Username" field. Fill in the remaining information, including your business address, and select the shipping methods you want to enable.
  • When you're done, click the Save and Continue
  • The next page will be your Shipping groups page. If you already have your Groups configured click on the Group you would like to add USPS too. If you have not configured your Shipping Groups do so at this time and click Save and Continue when done. 
  • In each zone, configure which USPS methods you would like to offer. Click Save and Continue on each zone(s) once you have added the USPS methods.