Enterprise Payment System Terms and Conditions

This Terms and Conditions of Use Agreement (this "Agreement") is a legal agreement between you ("You" or "Your" or "User" or "Mailer") and the United States Postal Service, an Independent Establishment of the Executive Branch of the United States Federal Government ("USPS" or "Postal Service"). The Agreement sets forth the terms and conditions for Your use of the USPS Enterprise Payment System. User acknowledges and agrees that he, she or the entity User has accepted the Agreement on behalf of is solely responsible for and shall abide by these Terms and Conditions of Use as well as all policies, procedures and regulations of the United States Postal Service.

Provisioning Mail Quality Data with Informed Visibility® Mail Tracking and Reporting

Mail Quality Data (MQD-IV) leverages the Informed Visibility^® Mail Tracking & Reporting (IV^®-MTR) application to enable mailers to receive uncapped Mail Quality Data. Detailed error data from the Mailer Scorecard is available for Full Service, Move Update, eInduction, and Seamless Acceptance.

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.

DELIVERY - WestPac Area - CO-WY District - Mesa Verde National Park Post Office - Resume Operations

Labeling List Changes Effective April 1, 2026

Effective April 1, 2026, the Postal Service™ will revise Labeling List(s) L002, L005, L007, L012, L016, L051, L201, and L606 to reflect changes in mail processing operations. Mailers are expected to label according to these revised lists for mailings inducted on or after the April 1, 2026, effective date through May 31, 2026, expiration date. The changes will be published in the Postal Bulletin, Issue #22698.

USPS APIs Release Notes

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

USPS® Approved Manufacturers of Mailing Containers for Adult Birds

A list of contact information for adult bird container manufacturers that have been certified by USPS.

Known Issues List 2.24.2026

Informational - USPS Webinar on AI, Direct Mail and Mailing Promotions