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.

Z4 Info File

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

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.

March 15 2026 Release Notes

INFORMATIONAL - Expansion of Daily USPS API On-Boarding Zoom Support

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.
 

USPS Business Portal (COP) Onboarding User Guide

The United States Postal Service (USPS)Business Portal (COP) offers business customers a modern, streamlined way to create and manage a USPS business account set-up and onboard core services.

Business Portal User Account Creation

Instructions for new USPS Business Customers to generate a new account.

MyPFS Portal in MPP Coming Soon - March 2026

Announcement of the release of the MyPFS product addition in My Product Portal. 

INFORMATIONAL - USPS Ship (Package Platform) - INCIDENT 10465287 Data delay, Impacting Multiple Data Feeds