If you have questions, please contact us by submitting a USPS API service request on the Email Us page and a representative will assist.

Please include the following information in your service request:

•Your Name
•Company Name
•Contact Phone Number
•Developer Portal Username
•Developer Portal App Name
•URL being called (apis.usps.com, apis-tem.usps.com, 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)