Signing Up for USPS shipping APIs

usps shipping api

Most ecommerce shopping carts  such as AbleCommerce, VevoCart and AspDotNetStorefront  use the United States Postal Service (USPS) to provide shipping rate calculations for purchases.  This requires that you sign up for a free USPS Web Tools account, and obtain the required API key.

Signing Up 

The USPS website provides a simple registration form that you must complete to gain access to the USPS Web Tools system.

1. In your browser, navigate to

2. Complete all the required fields of the registration form.

3. Click the Submit button.

You will see a confirmation page thanking you for registering.  You should receive a confirmation email within 24 hours.

Obtaining your API Credentials 

The confirmation email you receive from USPS will contain a username and password to use.  However, you will need to contact USPS for “Production Server Access” before these credentials will work.

1. In the confirmation email, locate and record the Username.

2. When prompted by a WebAssist product for your USPS user name and password, enter these credentials.

Obtaining Production Server Access 

In order for your product to be able to use the shipping rate lookup feature, you will need to request that USPS provide you with production server access.

1. Send an email to with the following information.

Subject: Production Server Access

Email Body:

I am using WebAssist’s PowerStore to provide an online store that includes a shipping rate lookup through USPS. In order for PowerStore to use this feature, I will need live production server access instead of the testing access I have so far.

My Username is 163W######

It may take a couple of days to receive a response, but once USPS moves your account to their production server, your shipping rate lookup should work with the credentials you received in the confirmation email.