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PostalOne! Release 64.0.0.0 Mail.XML PROD WSDLs
This ZIP file contains the Web Services Description Language (WSDL) and XML Schema Definition (XSD) files for Mail.XML™ PROD Release 64.0.0.0
06/16/2026
PostalOne! Release 64.0.0.0 Mail.XML TEM WSDLs
This ZIP file contains the Web Services Description Language (WSDL) and XML Schema Definition (XSD) files for Mail.XML™ TEM Release 64.0.0.0
06/16/2026
06/16/2026
PostalOne! Release 64.0.0.0 Mail.XML CAT WSDLs
This ZIP file contains the Web Services Description Language (WSDL) and XML Schema Definition (XSD) files for Mail.XML™ CAT Release 64.0.0.0
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05/28/2026
04/14/2026
03/11/2026
Merchant Onboarding and Authorization Tech Guide
Merchants need to follow a two-step process to authorize a Label Provider to generate shipping labels on their behalf.
1. Log in or create a USPS business account on the Customer Onboarding Portal (COP) to get Customer Registration ID (CRID), Mailer ID (MID), and Enterprise Payment Account (EPA). A CRID is a unique identifier for your company. A MID is another identifier which can be part of the barcode on a piece of mail.
2. Authorize Label Provider in COP. Before the merchant’s account can be used by Label Provider, Label Provider must be authorized. This will also enable Label Provider to generate package labels on behalf of NSA Holders at their NSA rates.
03/10/2026
01/09/2026