Featured Updates
06/08/2023
Publication 199 (Effective July 9, 2023): Intelligent Mail Package Barcode (IMpb) Implementation Guide for Confirmation Services and Electronic Payment Systems
This is a preview of Publication 199 which will be effective on July 9, 2023. For the current version please click here.
Tech Sheets for APIs, Click-N-Ship, and USPS Ship
Information on USPS offerings to help you streamline your shipping.
05/26/2023
05/03/2023
July 2023 Price Change Release Notes
Mail Dat Client update is mandatory for this Release.
05/19/2023
July 2023 Price Change Release Overview
Mail Dat Client update is mandatory for this Release.
02/13/2023
Caller/Reserve Transition to the Enterprise Payment System (EPS)
Effective July 1, 2023, customers without an EPS account will no longer be able to apply for or renew caller and reserve services at the retail counter.
Certified Full-Service Vendor Detailed List
This document contains a spreadsheet of detailed contact list information for Full-Service vendors.
01/17/2023
Parcel Return Service (PRS) Guide
Parcel Return Service is only available through a Negotiated Service Agreement (NSA) (709.1.0). Please consult this guide or contact a USPS Sales Representative for additional details.
11/22/2022
2D IMpb Barcode Guide
Some labels on packages may have barcodes that are not able to be scanned while being processed through automated equipment; this could be due to distortion, label placement, movement of items within soft packaging, etc.
08/18/2022
Seamless Acceptance Undocumented Mail Fact Sheet
Provides insight into the source of undocumented error reporting, common causes, and best practices.
06/03/2022
New Mailing Standards for the Separation of Hazardous Materials
The Postal Service has issued an interim final rule that will become effective upon publication in the Federal Register on June 6, 2022, with new requirements for the separation of hazardous materials (HAZMAT).
04/07/2022
Balance Check in the Customer Validation Tool Instructions
When given explicit permission by permit holders to do so, MSPs have the ability to perform balance checks for EPS and Local Trust accounts at the permit level.
03/04/2022
Informational Video for Shippers
This video provides helpful information for shippers and includes important USPS parcel shipping requirements.
06/01/2023
Publication for Streamlined Mail Acceptance for Letters and Flats (Pub 685)
Streamlined Mail Acceptance for Letters and Flats (Pub 685) contains the policies and processes for the verification of eligible business mailings using tools provided by Intelligent Mail® Full-Service, eInduction, and Seamless Acceptance.
07/14/2022
04/24/2023
USPS Post Office & Collection Box Data
Datasets containing the specific coordinates of United States Postal Service Post Offices and blue collection boxes as well as detailed information around specific services offered and hours of operations or collection times.
11/18/2021
CRID Management
Customer Registration ID (CRID) Overview.
03/23/2021
Latest Updates
06/08/2023
06/08/2023
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.
06/08/2023
Z4 Info File
A downloadable ZIP file containing information related to the Z4 Info File
06/08/2023
06/08/2023
Publication 199 (Effective July 9, 2023): Intelligent Mail Package Barcode (IMpb) Implementation Guide for Confirmation Services and Electronic Payment Systems
This is a preview of Publication 199 which will be effective on July 9, 2023. For the current version please click here.
PostalOne! Contingency Plan
Learn what to do in the event a system outage prevents you from submitting your mailing information electronically.
USPS Service Alerts
Receive near real-time notifications about postal facility service disruptions due to weather-related outages and other natural disasters or events.
Stay Informed About Postal Policy
Updated daily, the Federal Register Notices offer detailed information regarding official USPS policy and regulatory changes.
Intelligent Mail: Featured Resources

Publication for Streamlined Mail Acceptance for Letters and Flats (Pub 685)
Streamlined Mail Acceptance for Letters and Flats (Pub 685) contains the policies and processes for the verification of eligible business mailings using tools provided by Intelligent Mail® Full-Service, eInduction, and Seamless Acceptance.