Unique ZIP® Code Flowchart

This flowchart describes the logic flow for Unique ZIP codes.

PS Form 3553: CASS™ Summary Report

This form is the CASS™ Summary Report.

Unique ZIP® Code Matrix

The Unique ZIP Code Matrix displays Carrier Route ID, Record Type, and Delivery Point assignment rules within unique ZIP codes only.

PS Form 3553: CASS™ Summary Report

This form is the CASS™ Summary Report.

Z4 Info File

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

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

CASS™ Certified Products Guide: M L O C R Service Bureaus Data File Cycle O - (Expires July 31, 2028)

CASS™ Certified Products Guide: M L O C R Service Bureaus 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.

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

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

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

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

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

CASS™ Certified Products Guide: Residential Delivery Indicator Cycle O - (Expires July 31, 2028)

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.

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: M L O C R Hardware Manufacturers Data File Cycle O - (Expires July 31, 2028)

CASS™ Certified Products Guide: Z4CHANGE Cycle O - (Expires July 31, 2028)

CASS™ Certified Products Guide: Z4CHANGE Data File Cycle O - (Expires July 31, 2028)

CASS™ Certified Products Guide: M L O C R Hardware Manufacturers Cycle O - (Expires July 31, 2028)

CASS™ Certified Products Guide: M L O C R Mailers/Users Cycle O - (Expires July 31, 2028)

CASS™ Certified Products Guide: M L O C R Mailers/Users Data File Cycle O - (Expires July 31, 2028)

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

CASS™ Certified Products Guide: M L O C R Service Bureaus Data File Cycle O - (Expires July 31, 2028)

CASS™ Certified Products Guide: M L O C R Hardware Manufacturers Cycle O - (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™ Certified Products Guide: Z4CHANGE Cycle O - (Expires July 31, 2028)

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.

RDI™ Cycle O: Certified Products Guide (D) - (Expires July 31, 2028)

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

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

CASS™ Certified Products Guide: M L O C R Hardware Manufacturers Data File Cycle O - (Expires July 31, 2028)

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

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

CASS™ Certified Products Guide: M L O C R Mailers/Users Cycle O - (Expires July 31, 2028)

CASS™ Certified Products Guide: Residential Delivery Indicator Cycle O - (Expires July 31, 2028)

CASS™ Certified Products Guide: Z4CHANGE Data File Cycle O - (Expires July 31, 2028)

RDI™ Cycle O: Certified Products Guide (D) - (Expires July 31, 2028)

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

Z4 Info File

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

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

CASS™ Certified Products Guide: M L O C R Service Bureaus 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.

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

CASS™ Certified Products Guide: M L O C R Mailers/Users Data File Cycle O - (Expires July 31, 2028)

CASS™ Technical Guide for Cycle O

This document provides a technical guide for the CASS™ product. The CASS certification process is designed in cooperation with the mailing industry to improve the accuracy and deliverability of addresses for mail qualifying for postal discounts.

CASS™ and MASS™ Certified Products Guide Cycle: 2023-2028

CASS™ and MASS™ Certified Products Guide Cycle: 2023-2028

Cycle O EWS Static Data File

CASS™ Certified Products Guide: M L O C R Service Bureaus Data File Cycle N - (Expires July 31, 2023)

CASS™ Certified Products Guide: M L O C R Service Bureaus Cycle N - (Expires July 31, 2023)

CASS™ Software Manufacturers Data File Cycle N: Certified Products Guide (D) - (Expires July 31, 2023)

This document contains the CASS™/MASS™ certified vendors list for CASS™ software manufacturers for Cycle N.

DSF2® Licensees Cycle N: Certified Products Guide - (Expires July 31, 2023)

This document contains the CASS™/MASS™ certified vendors list for DSF2® Licensees for Cycle N.

CASS™ Certified Products Guide: M L O C R Hardware Manufacturers Cycle N - (Expires July 31, 2023)

CASS™ Certified Products Guide: M L O C R Hardware Manufacturers Data File Cycle N - (Expires July 31, 2023)

CASS™ Certified Products Guide: Vendor/Service Bureaus Licensees Cycle N - (Expires July 31, 2023)

CASS™ Certified Products Guide: Vendor/Service Licensees Data File Cycle N - (Expires July 31, 2023)

CASS™ Certified Products Guide: DSF2® Licensees Data File Cycle N - (Expires July 31, 2023)

DPV® Licensees Cycle N: Certified Products Guide - (Expires July 31, 2023)

This document contains the CASS™/MASS™ certified vendors list for DPV® Licensees Cycle N.

DPV® Licensees Data File Cycle N: Certified Products Guide (D) - (Expires July 31, 2023)

This document contains the CASS™/MASS™ certified vendors list for DPV® Licensees Data File for Cycle N.

CASS™/MASS™ Certified Products Guide - All Sections Data Files Cycle N - (Expires July 31, 2023)

This document contains the certified vendors list for CASS™ and MASS™ products for Cycle N.

CASS™ Software Manufacturers Cycle N - (Expires July 31, 2023)

This document contains the CASS™/MASS™ certified vendors list for CASS software manufacturers for Cycle N.

CASS™ Certified Products Guide: Z4CHANGE Data File Cycle N - (Expires July 31, 2023)

CASS™ Certified Products Guide: M L O C R Mailers/Users Cycle N - (Expires July 31, 2023)

CASS™ Certified Products Guide: Z4CHANGE Cycle N - (Expires July 31, 2023)

CASS™ Certified Products Guide: Residential Delivery Indicator Cycle N - (Expires July 31, 2023)

RDI™ Cycle N: Certified Products Guide (D) - (Expires July 31, 2023)

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

DPV® Licensees Cycle N: Certified Products Guide - (Expires July 31, 2023)

This document contains the CASS™/MASS™ certified vendors list for DPV® Licensees Cycle N.

CASS™ Certified Products Guide: M L O C R Service Bureaus Cycle N - (Expires July 31, 2023)

DSF2® Licensees Cycle N: Certified Products Guide - (Expires July 31, 2023)

This document contains the CASS™/MASS™ certified vendors list for DSF2® Licensees for Cycle N.

CASS™ Certified Products Guide: M L O C R Hardware Manufacturers Data File Cycle N - (Expires July 31, 2023)

CASS™ Software Manufacturers Cycle N - (Expires July 31, 2023)

This document contains the CASS™/MASS™ certified vendors list for CASS software manufacturers for Cycle N.

CASS™ Certified Products Guide: Vendor/Service Bureaus Licensees Cycle N - (Expires July 31, 2023)

CASS™ Certified Products Guide: M L O C R Mailers/Users Cycle N - (Expires July 31, 2023)

CASS™ Certified Products Guide: M L O C R Hardware Manufacturers Cycle N - (Expires July 31, 2023)

RDI™ Cycle N: Certified Products Guide (D) - (Expires July 31, 2023)

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

CASS™ Certified Products Guide: M L O C R Mailers/Users Data File Cycle N - (Expires July 31, 2023)

CASS™ Certified Products Guide: M L O C R Service Bureaus Data File Cycle N - (Expires July 31, 2023)

CASS™ Certified Products Guide: DSF2® Licensees Data File Cycle N - (Expires July 31, 2023)

CASS™ Software Manufacturers Data File Cycle N: Certified Products Guide (D) - (Expires July 31, 2023)

This document contains the CASS™/MASS™ certified vendors list for CASS™ software manufacturers for Cycle N.

CASS™ Certified Products Guide: Vendor/Service Licensees Data File Cycle N - (Expires July 31, 2023)

CASS™ Certified Products Guide: M L O C R Mailers/Users Data File Cycle N - (Expires July 31, 2023)

DPV® Licensees Data File Cycle N: Certified Products Guide (D) - (Expires July 31, 2023)

This document contains the CASS™/MASS™ certified vendors list for DPV® Licensees Data File for Cycle N.

CASS™ Certified Products Guide: Residential Delivery Indicator Cycle N - (Expires July 31, 2023)

CASS™/MASS™ Certified Products Guide - All Sections Data Files Cycle N - (Expires July 31, 2023)

This document contains the certified vendors list for CASS™ and MASS™ products for Cycle N.

CASS™ Certified Products Guide: Z4CHANGE Data File Cycle N - (Expires July 31, 2023)

CASS™ Certified Products Guide: Z4CHANGE Cycle N - (Expires July 31, 2023)

CASS™ Cycle O - Executive Summary

Z4CHANGE Order Form

This order form is used to subscribe to the Z4CHANGE product. 

Z4CHANGE Order Form

This order form is used to subscribe to the Z4CHANGE product. 

CASS™ Order Form

This document contains the order form for CASS™.

CASS™ Order Form

This document contains the order form for CASS™.

Terms and Conditions for CASS™ Software Developers

This document outlines the terms and conditions for CASS™ certification for developers.

Terms and Conditions for CASS™ End Users

This document outlines the terms and conditions for CASS™ certification for end users.

Terms and Conditions for CASS™ Software Developers

This document outlines the terms and conditions for CASS™ certification for developers.

Terms and Conditions for CASS™ End Users

This document outlines the terms and conditions for CASS™ certification for end users.

Electronic Product Fulfillment (EPF) Web Access Request Form (PS 5116)

This form is used to create a Web-based account with the Addressing and Geospatial Technology (AGT) office which will be utilized to retrieve/download files from the Electronic Product Fulfillment (EPF) website.

Electronic Product Fulfillment (EPF) Web Access Request Form (PS 5116)

This form is used to create a Web-based account with the Addressing and Geospatial Technology (AGT) office which will be utilized to retrieve/download files from the Electronic Product Fulfillment (EPF) website.

TotalDPS – Programmer Specs

This document provides information for calculating TotalDPS.

Modifications to TotalDPS – Programmers Specs file

Changes made to the Total DPS document

CASS™ Cycle O - Stage I File

This file only contains CASS™ Cycle O enhancements.

DPV® & DSF2® Return Codes and Footnote Possibilities

This file contains sample addresses that include the DPV/DSF2 Return Codes and Footnotes.

Alpha Stage 1 File Analysis

This file contains only known errors in the Alpha Stage 1 File. The file has a Search functionality on the first record of the file on the “KEY” field. The search should include the 8-digit CASS key at positions 8-21 in the Alpha Stage 1 file.

CASS™ Cycle O Partnership In Tomorrow Final Rules - September 2020 (Updated)

CASS™ Cycle O Implementation Rescheduled to August 2023

CASS™ Cycle O Rescheduled

CASS™ Stage 1 file DPV header record

CASS™ Cycle O Partnership in Tomorrow Minutes

CASS™ Cycle O Partnership in Tomorrow Q & A

CASS™ Technical Guide for Cycle N

This document provides a technical guide for the CASS™ product. The CASS™ certification process is designed in cooperation with the mailing industry to improve the accuracy of addresses for mail qualifying for postal discounts.

CASS™ Technical Guide for Cycle N

This document provides a technical guide for the CASS™ product. The CASS™ certification process is designed in cooperation with the mailing industry to improve the accuracy of addresses for mail qualifying for postal discounts.

CASS™ Cycle N Disclaimer for Stage 1 file processed with SHA 256 static data

CASS™ Cycle N Disclaimer for Stage 1 file processed with SHA 256 static data

CASS™ Cycle N - Stage 1 file processed with SHA 256 data

CASS™ Cycle N - Stage 1 file processed with SHA 256 data

CASS™ MASS™ Test Files on EPF

Postal Addressing Standards for Puerto Rico and US Virgin Island (English)

Postal Addressing Standards for Puerto Rico and US Virgin Island (English).

Postal Addressing Standards for Puerto Rico and US Virgin Island (Spanish)

Postal Addressing Standards for Puerto Rico and US Virgin Island (Spanish).

Developer's Guide for CASS™ Vendors

This document provides a vendor's guide for CASS™ development.

CASS™ and MASS™ Cycle O Deferment Letter

This letter announces the deferment of CASS™/MASS™ Cycle O implementation.

R11 RDI™ Cycle M Static Data

This zip file contains RDI 11-digit static data for Cycle M.

CASS™ Cycle N Stage I File

This zip file is for categories only processed with 2009-2011 Cycle N static data.

Early Warning System (EWS) Cycle N Static Data

This zip file contains Early Warning System Data for Cycle N.

Delivery Type Cycle N Static Data

This text file provides delivery type Cycle N static data

R11 RDI™ Cycle N Static Data

This zip file contains RDI 11-digit static data.

R9 RDI™ Cycle N Static Data

This zip file contains RDI 9-digit static data.

EWS Data used with the NATLSTG1M.ZIP file

This zip file contains EWS data associated with the Stage 1 File. 

DPV® Vacant Table Cycle M Static Data

This data file provides static data for DPV® Vacant Table Cycle M.

R9 RDI™ Cycle M Static Data

This zip file contains RDI 9-digit static data for Cycle M.

Enhanced Line of Travel (eLOT) Cycle M Static Data

This zip file contains static data for eLot Cycle M.

CASS™ Cycle L Issues

This document provides policy clarifications to CASS Cycle L requirements that have been identified.

CASS™ Cycle N Partnership in Tomorrow Minutes

The Partnership in Tomorrow Meeting was hosted by the National Customer Support Center in Memphis, TN with attendees and webinar participants from various industry representatives.

CASS™ Cycle N Partnership in Tomorrow Presentation

This Partnership in Tomorrow presentation reviews CASS/MASS Cycle M and N requirements.

CASS™ and MASS™ Cycle N Deferment Letter

The implementation date for CASS/MASS Cycle N is being deferred to August 1, 2011.

Licensing Announcement: CASS™ Cycle L Reminder

As a reminder, the CASS™ 2006-2007 (Cycle K) version of the AMS API Product ceased to function effective August 1, 2007.

DPV®, DSF2®, CASS™ Grading Requirements

This document contains grading requirements for DPV®, DSF2®, and CASS™ products.

CASS™ and MASS™ Guidelines