If you want to use the United States Postal Service (USPS) for real-time shipping rates you need to establish an account and have the account activated on the USPS production server. There is no need to test anything since Kryptronic has done all of the testing with USPS for you.

You may complete all of the steps detailed in admin under Store > Shipping > USPS WebTools to begin using real-time shipping rates from USPS immediately. If you do not complete steps 4 and 5 any testing you do with USPS selected will default to the standard carrier rate and/or other carriers you may have selected.

Here is a recap of the steps required to obtain and activate an account with USPS:

1. Visit the USPS web site at http://www.uspswebtools.com/ and click the registration link that’s presented.

2. Complete all of the information requested on the registration page, be sure to agree to the USPS WebTools terms and conditions and submit the form.

3. After submitting the form you will recieve a username along with a development URL via email. Save the username and disregard the development URL.

4. Between 7:00 AM and 11:00 PM Eastern time, call the USPS Internet Customer Care Center center and speak to a representative. Provide the representative with your username, inform them that you have completed testing your integration, and are ready to have access to the production server. The representative will send you an email with the production server URL.

5. Once you receive the production server URL via email from USPS, your account is production-ready.