Announcements
12/26/2025
DELIVERY - Wrightwood Post Office (92397) - Temporarily Closed
Announcements
12/26/2025
DELIVERY - Lytle Creek Post Office (92358) - Temporarily Closed
Data Files
12/26/2025
Z4 Info File

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

Data Files
12/26/2025
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.

 

Announcements
12/23/2025
INFORMATIONAL - USPS APIs System Maintenance January 14, 2026
Data Files
12/22/2025
12_22_25_PTR2 Release Notes
Announcements
12/22/2025
INFORMATIONAL - Postal Service Files Requests for New Rules on Market Dominant Rates
Announcements
12/22/2025
INFORMATIONAL - MGI Important Dates
FAQs
12/22/2025
USPS PTR2 API Known Issues
Announcements
12/19/2025
INFORMATIONAL - January Price Change 2026 - Commercial System Releases January 4