After you’ve completed your development in the Customer Acceptance Testing (CAT) environment, follow these steps to start using the USPS APIs:

1. Log In/Create USPS Business Account

Use the USPS Customer Onboarding Portal (COP), sign into your USPS Business Account, or create a new USPS Business Account. The COP will ensure that your USPS Business Account is configured for the USPS APIs.

2. Log In

Log in to the USPS Developer Portal using your USPS Business Account credentials from Step 1

3. Create an App

After logging into the Developer Portal, click the Apps button from the Menu Bar and complete the following steps to create an App:

1.Click "Add App"
2.Enter your App Name (required)
3.Enter your Callback URL (optional)
4.Check the box to accept Terms and Conditions and Privacy Policy
5.Enter Description (optional)
6.Select API Product (required)
7.Click "Add App"

4. Retrieve your Consumer Key and Secret 

Select your App and retrieve your Consumer Key and Consumer Secret from the Credentials section. These credentials are required for the next step and for generating the OAuth Token.

5. Authorize App to Access Protected Information Resources

Enter your Consumer Key here to authorize your App to access your payment accounts, permits, CRIDs, MIDs, and subscriptions, which will be required by several USPS APIs.

6. Generate your OAuth Token

Review the OAuth specifications and scroll down to the “Generate OAuth Tokens” sections. Pass the Consumer Key and Consumer Secret obtained in Step 4 as the client_id and client_secret, respectively.

7. Try Out USPS APIs

Review the API Catalog for the detailed specifications on the available APIs. All USPS APIs require an OAuth Token to be conveyed in the Authorization header, using the Bearer Token scheme. Please reference the USPS Github page for a repository that contains example Postman requests and Curl commands.

The default product includes OAuth, Addresses, Domestic Pricing, International Pricing, Locations, Service Standards, and Shipping Options, each with a quota of 60 calls per hour. To get started with APIs not included in the default or to request a quota increase, please contact APISupport@usps.gov and a representative will assist you. 

Note: If you want to use the Labels APIs, it requires additional approval and configuration. The Labels APIs require you to be enrolled in USPS Ship for both outbound and return labels and have an Enterprise Payment Account.  

Contact Us:

If you have questions, please contact us at APISupport@usps.gov. In your email, please include the following information:

•Your Name
•Company Name
•Contact Phone Number
•Developer Portal Username
•Developer Portal App Name
•URL being called (api.usps.com or api-cat.usps.com)
•Consumer Key/client_id
•Customer Registration ID (CRID)
•Mailer ID (MID)
•Country
•ZIP Code

**Do not include Consumer Secret (client_secret)