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05/28/2026
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04/14/2026
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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.
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03/10/2026
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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
05/28/2026
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.