Boxify obtains USPS rates from rating APIs provided by the USPS Web Tools service. Getting access to those APIs requires two distinct steps:
The first step is to register with USPS Web Tools by filling out this online registration form with USPS.
It may take up to an hour for USPS Web Tools to issue you credentials (a username and password), which will be sent to the email address that you used when registering.
Once you receive the email message from USPS Web Tools with your Web Tools username and password, send USPS Web Tools the information it requests in part 3 of its message. Supply the requested information as follows:
Username/User ID: [Provide the Web Tools username/USERID you were given in the email Web Tools sent to you. ]
USPS Mailer ID: [Answer with, "I am a Shopify merchant and do not have my own Mailer ID."]
Company website: [Provide the URL of your Shopify shop.]
List the API(s) for which your are requesting access" [Answer with, "The rating APIs (RateV4 and IntlRateV2)."]
Expected volume... [If you can estimate what your sales volumes might be, you could indicate those estimates here. Or just write, "I am a new business and do not know what peak volumes my online shop might experience."]
Are you a shipper or software provider? Please provide details on how your business will use the APIs. [Answer with, "Shipper. Our business will be using the Web Tools rating APIs to display USPS rates at checkout to customers in our ecommerce shop."]
Are you using a third-party software/software provider...? [Answer with, "BOXIFY." It's important to mention Boxify here to expedite the approval process.]
Any additional information...? [Answer with, "Thanks in advance!"]
USPS Web Tools should respond with an email message indicating that you have been given access to its rating APIs, at which point you can go to the Boxify dashboard, scroll down to the section on shipping carriers and click on the button marked, "Configure USPS." Enter your USPS Web Tools username and select which USPS rate tier you want to display to your customers.