Contact Lists
11/13/2025
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.

Presentations
11/12/2025
Addressing Modernization - API
Fact Sheets
11/12/2025
USPS Ship Package Data Feeds

This document outlines the steps for shippers to access package data feeds through the USPS Informed Visibility Mail Tracking & Reporting (IV-MTR) application.

Technical Specifications
11/12/2025
Addressing API Specifications
Technical Specifications
11/12/2025
Addressing API - Vendors
Technical Specifications
11/12/2025
Addressing API - End Users - Tech Sheet
FAQs
11/12/2025
USPS PTR2 API Known Issues
Announcements
11/12/2025
PTR Modernization

PTR is being modernized to deliver a best-in-class visibility solution for customers. The new solution, PTR 2, will provide a scalable and highly available platform to support continued package volume growth and evolving business functionality to deliver exceptional customer value.

Tech Guides
11/12/2025
Guide to USPS Ship
Tech Guides
11/12/2025
USPS Ship Tech Sheet

USPS Ship is a modernized platform enabling commercial package payment, verification, and end-to-end visibility for a wide array of domestic and international products.