Contact Lists
12/04/2025
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
12/04/2025
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.

Data Files
12/04/2025
Z4 Info File

A downloadable ZIP file containing information related to the Z4 Info File

Data Files
12/04/2025
Early Warning System (EWS002C0.ZIP)

This file is the EWS production file and is updated weekly. This file contains the Early Warning System data file for the CASS™ and MASS™ certification process.

 

Data Files
12/03/2025
Data Files
12/03/2025
NCOALink® Statistics

This spreadsheet includes NCOALink statistics from 2007-2025 by licensee type.

Fact Sheets
12/03/2025
Addressing Fact Sheet for USPS Marketing Mail Flats

This document is for business mailers who are sending flat-size USPS Marketing Mail (such as large envelopes, catalogs, and circulars). To use the USPS Marketing Mail prices, you must send at least 200 pieces or 50 pounds of mail at a time, prepared and sorted according to Postal Service guidelines.