Tech Guides
09/03/2026
Informed Visibility® Mail Tracking & Reporting (IV®-MTR) Mail.XML Guide

This guide provides information about using MailXML™ to receive mail tracking data through the IV-MTR application. Through Mail.XML, mailers can receive visibility information for letter and flat containers and handling units (trays, tubs, and sacks).

Release Notes
09/02/2026
USPS APIs Release Notes

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

Data Files
09/01/2026
August 2026 Nixie Volume

This spreadsheet contains the UAA statistics for August 2026.

Error Codes
09/01/2026
Contact Lists
09/01/2026
MPE (Mail Processing Equipment) Service Provider Licensees

Marketing contact information for certified Mail Processing Equipment (MPE) licensees 

Publications
08/31/2026