Data Files
05/01/2026
ZIP Codes by Area and District codes

The Excel spreadsheet lists ZIP Codes with the associated Area and District Codes.  

Announcements
04/30/2026
INFORMATIONAL - Officer Appointments - Chief Solutions & Strategy Officer and Vice President of Network Solutions & Performance Excellence
Announcements
04/30/2026
DELIVERY - Falkland Post Office (27827) - Temporarily Closed
Announcements
04/30/2026
INFORMATIONAL: Mail Spoken Here - April Issue
Publications
04/30/2026
PCC Insider April 2026 Edition
Contact Lists
04/30/2026
CASS™ Certified Products Guide: Residential Delivery Indicator Cycle O - (Expires July 31, 2028)
Contact Lists
04/30/2026
RDI™ Cycle O: Certified Products Guide (D) - (Expires July 31, 2028)

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

Contact Lists
04/30/2026
CASS™ Certified Products Guide: M L O C R Mailers/Users Data File Cycle O - (Expires July 31, 2028)
Contact Lists
04/30/2026
CASS™ Certified Products Guide: M L O C R Mailers/Users Cycle O - (Expires July 31, 2028)
Contact Lists
04/30/2026
CASS™ Certified Products Guide: M L O C R Service Bureaus Data File Cycle O - (Expires July 31, 2028)
Contact Lists
04/30/2026
CASS™ Certified Products Guide: M L O C R Service Bureaus Cycle O - (Expires July 31, 2028)
Contact Lists
04/30/2026
CASS™ Certified Products Guide: M L O C R Hardware Manufacturers Data File Cycle O - (Expires July 31, 2028)
Contact Lists
04/30/2026
CASS™ Certified Products Guide: M L O C R Hardware Manufacturers Cycle O - (Expires July 31, 2028)
Contact Lists
04/30/2026
CASS™ Certified Products Guide: Z4CHANGE Data File Cycle O - (Expires July 31, 2028)
Contact Lists
04/30/2026
CASS™ Certified Products Guide: Z4CHANGE Cycle O - (Expires July 31, 2028)
Contact Lists
04/30/2026
CASS™ Certified Products Guide: Vendor/Service Licensees Data File Cycle O - (Expires July 31, 2028)
Contact Lists
04/30/2026
CASS™ Certified Products Guide: Vendor/Service Bureaus Licensees Cycle O - (Expires July 31, 2028)
Contact Lists
04/30/2026
CASS™ Certified Products Guide: DSF2® Licensees Data File Cycle O - (Expires July 31, 2028)
Contact Lists
04/30/2026
DSF2® Licensees Cycle O: Certified Products Guide - (Expires July 31, 2028)
Contact Lists
04/30/2026
DPV® Licensees Data File Cycle O: Certified Products Guide (D) - (Expires July 31, 2028)
Contact Lists
04/30/2026
DPV® Licensees Cycle O: Certified Products Guide - (Expires July 31, 2028)
Contact Lists
04/30/2026
CASS™ Software Manufacturers Data File Cycle O: Certified Products Guide (D) - (Expires July 31, 2028)
Contact Lists
04/30/2026
CASS™ Software Manufacturers Cycle O - (Expires July 31, 2028)
Contact Lists
04/30/2026
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
04/30/2026
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.