Contact Lists
12/20/2024
Mail Service Provider (MSP) - Full-Service Certified Mailers

A Mail Service Provider (MSP) offers a variety of solutions to prepare and present Full-Service presort mailings. For more information regarding Certified MSPs, please follow this link: https://postalpro.usps.com/full-service-cert/fact-sheet

 

Release Notes
12/19/2024
USPS APIs Release Notes

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

Data Files
12/19/2024
Z4 Info File

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

Publications
12/19/2024
Publication 401: Guide to the Manifest Mailing System

This publication provides information on the Manifest Mailing System, which automates the documentation of postage and fees for all pieces in a mailing paid via permit imprint indicia.

Data Files
12/19/2024
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.