06/16/2026
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
05/28/2026
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
01/06/2026
01/06/2026
USPS Ship Tech Sheet
USPS Ship is a modernized platform enabling commercial package payment, verification, and end-to-end visibility for a wide array of domestic and international products.
01/02/2026
Labeling Lists Technical Guide
The Labeling Lists data product assists mailers with presorting mail. It provides active, originating 3- and 5-digit ZIP Code™ data along with their destination locations [including city/state/ZIP Code] for labeling purposes. The product contains complete data files of each list found online via Postal Explorer® at https://pe.usps.com. Updates to the Labeling Lists are also published in the Postal Bulletin.
11/26/2025
PostalOne! Release 63.0.0.0 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 63.0.0.0
11/26/2025
11/26/2025
PostalOne! Release 63.0.0.0 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 63.0.0.0
11/26/2025
PostalOne! Release 63.0.0.0 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 63.0.0.0
10/06/2025
10/06/2025
Intelligent Mail Container Barcode Technical Specifications
Technical specifications for printing the USPS Intelligent Mail® Container barcode (IM™ Container barcode). The Intelligent Mail Container barcode is used on mailer-generated pallet labels to uniquely identify pallets and similar containers (i.e. All Purpose Containers, hampers, pallet boxes, etc.) in addition to identifying the mail owner.
07/24/2025
07/07/2025
Intelligent Mail Tray Label Technical Fact Sheet
This document provides fact sheet providing technical specifications on the acquisition, implementation, and benefits of the Intelligent Mail Tray Label.
06/18/2025
PostalOne! Release 62.0.0.0 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 62.0.0.0
06/18/2025
06/18/2025
PostalOne! Release 62.0.0.0 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 62.0.0.0
06/18/2025
PostalOne! Release 62.0.0.0 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 62.0.0.0