CASS™ Certified Products Guide: Vendor/Service Licensees Data File Cycle O - (Expires July 31, 2028)

CASS™ Certified Products Guide: Vendor/Service Bureaus Licensees Cycle O - (Expires July 31, 2028)

CASS™ Certified Products Guide: DSF2® Licensees Data File Cycle O - (Expires July 31, 2028)

DSF2® Licensees Cycle O: Certified Products Guide - (Expires July 31, 2028)

DPV® Licensees Data File Cycle O: Certified Products Guide (D) - (Expires July 31, 2028)

DPV® Licensees Cycle O: Certified Products Guide - (Expires July 31, 2028)

CASS™ Software Manufacturers Data File Cycle O: Certified Products Guide (D) - (Expires July 31, 2028)

CASS™ Software Manufacturers Cycle O - (Expires July 31, 2028)

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.

Informed Visibility® Mail Tracking & Reporting (IV®-MTR) Release Notes

These release notes summarize new features and enhancements implemented in deployments to the IV-MTR application.

Business Acceptance Solutions & Major Mailer Support Directory

This document provides a contact list for Business Acceptance Solutions (formerly Business Mailer Support) & Major Mailer Support

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.

INFORMATIONAL - UPDATE - Manifest Quality (MQ) Noncompliance

Known Issues List 9.15.2026

USPS APIs Release Notes

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

USPS® Post Office and Blue Collection Box Location Dataset Briefing Sheet

Occupancy Trends License Agreement

USPS Population Mobility Trends License Agreement (Sample Only)

Population Mobility Trends Order Form

United States Postal Service Post Office™ and Collection Box Products Data License Agreement

Post Office™ and Collection Box Products Order Form

DELIVERY - Janesville Post Office (56048) - Temporarily Closed

September 2026 PCC Events Calendar

Mailers Technical Advisory Committee (MTAC): Association Membership Form

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.
 

PROCESSING AND DISTRIBUTION - Central Processing Region - Louisville, KY Processing and Distribution Center (P&DC) Delays

PCC Events (September 2026)

INFORMATIONAL - New USPS NCOA API – Launching October 4, 2026

September 20, 2026 - FAST R69.0.1.0 Release Notes

Cumulative Listing of ZIP Codes Covered by the LACS Database

This document provides a cumulative listing of ZIP Codes covered by the LACS database for LACS^Link®.

DSF2® Licensees

This document contains a list of DSF^2® licensed providers with contact information.

DPV® Licensees

This document provides a contact list of licensees for DPV^®.

INFORMATIONAL - October Time-Limited Price Change 2026 PostalOne! Alert – September 20, 2026

INFORMATIONAL - October Time-Limited Price Change 2026 Commercial System Releases – September 20, 2026

INFORMATIONAL - UPDATE - Commercial System Releases – Week of September 12, 2026

Request to Lead or Participate - MTAC User Group and Work Group

Chief Retail & Delivery PCC Board Support Role

PCCAC Certification Webinar: Address Hygiene with Adam Collinson

INFORMATIONAL - 2027 National Postal Forum Registration Now Open

2027 National Postal Forum Registration Now Open

NCOALink® Limited Service Provider Licensees

This document provides a list of service providers and contact information for NCOA^Link®. These providers receive 18 months of change-of-address (COA) data on a weekly basis from the USPS^®. For the full 48 months of COA data refer to the NCOA^Link Full Service Provider Licensees.

DELIVERY - El Portal Post Office – Resume Operations

INFORMATIONAL - USPS APIs System Release Notification - September 16, 2026

Informed Visibility Mail Tracking & Reporting Machine Count

List of US Postal Service machines by site, including a description of each machine.

ZIP Codes by Area and District codes

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

Automated Zone Indicator (AZI) Table

The AZI table lists each five-digit ZIP Code™ and is an indicator of the type of processing that typically takes place on letter mail destined for each ZIP Code. Each number in the file is a ZIP Code appended with a numeric zone indicator. The five numeric indicators are as follows:

1. Two Pass Zones: Automated two-step sector/segment at mail processing facilities
2. 876 Carrier Route Sort Zones: Automated incoming secondary carrier route sorting at plants
3. Carrier Route Barcode Sorter (CSBCS) Zones: Automated walk sequence sorting on CSBCS machines at delivery units
4. Delivery Barcode Sorter (DBCS) Zones: Automated walk sequence sorting on DBCS machines at plants [i.e., sectional center facilities (SCFs)] or at delivery units
5. Manual/Mechanized Zones: No automated sorting; no tracking code scans should be generated from facilities matched to these ZIP Codes

INFORMATIONAL - USPS APIs System Patching Notification – September 5 and 6, 2026

DELIVERY - Big Sur Post Office – Resumes Operations

INFORMATIONAL - Commercial System Releases – Week of September 12, 2026