Program Requirements
06/18/2026
Program Requirements
06/18/2026
Program Requirements
06/18/2026
Program Requirements
06/18/2026
Program Requirements
06/18/2026
Applications/ Forms
06/18/2026
Release Notes
06/18/2026
USPS APIs Release Notes

For the latest updates, please review the USPS APIs Release Notes.

Contact Lists
06/18/2026
RDI™ Cycle O: Certified Products Guide (D) - (Expires July 31, 2028)

This document outlines the CASS/MASS certified vendors list for RDI™ Cycle O.