Data Files
11/20/2025
Z4 Info File

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

Data Files
11/20/2025
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.

 

Release Notes
11/19/2025
Tracking API Access Control Changes Release Overview
Announcements
11/19/2025
DELIVERY - Southern Area – South Carolina District Sunset Post Office (29685) – Closed Indefinitely
User Guides
11/19/2025
Mailing and Shipping Solutions Center (MSSC) Topics

List of topics the MSSC can assist with. To reach the MSSC, email us at MSSC@usps.gov or call 1-877-672-0007 from 7:00AM – 7:00PM CT.

Presentations
11/18/2025
Addressing and NCOALink Modernization
Release Notes
11/18/2025
USPS APIs Release Notes

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

FAQs
11/17/2025
Modernization of Address & NCOA Processing with APIs - Q & A
FAQs
11/17/2025
USPS Ship Frequently Asked Questions

USPS Ship Frequently Asked Questions

Data Files
11/17/2025
***Updated - New Areas*** - Area District 5-digit ZIP Codes (AREADIST_ZIP5.TXT)