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USPS APIs Release Notes
For the latest updates, please review the USPS APIs Release Notes.
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RDI™ Cycle O: Certified Products Guide (D) - (Expires July 31, 2028)
This document outlines the CASS/MASS certified vendors list for RDI™ Cycle O.
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Contact Lists
04/16/2026
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CASS™/MASS™ Certified Products Guide - All Sections Data Files Cycle O - (Expires July 31, 2028)
This document contains the certified vendors list for CASS™ and MASS™ products for Cycle O.
Data Files
04/16/2026
04/16/2026
USPS Ship Data Dictionary
Detailed information on the USPS Ship (Formerly Package Platform) data elements available through the Informed Visibility Mail Tracking & Reporting (IV-MTR) application. Please note that items in bold text were updated or added recently.