CASS

Coding Accuracy Support System

A certification program developed by the United States Postal Service (USPS) to ensure the accuracy and standardization of addresses in mailing databases. Its primary goal is to improve deliverability, reduce undeliverable mail, and enable businesses to qualify for postal discounts by verifying that address data complies with USPS formatting and coding standards.

CASS certification applies to software solutions used by mailers, service bureaus, and data providers to process address lists accurately and efficiently. These software systems compare input addresses against the USPS Address Management System, correcting elements such as ZIP Codes, street names, city names, and directional information. A key outcome of this process is the generation of a standardized, delivery-point validated address that aligns with USPS expectations.

CASS-certified software can perform a variety of corrections and enhancements, including:

• Verifying street names and numbers.
• Standardizing address abbreviations.
• Appending missing ZIP+4 codes.
• Identifying delivery points and carrier routes.
• Flagging potentially undeliverable or non-existent addresses.

To maintain certification, software vendors must pass USPS testing regularly, ensuring their systems are up-to-date with address data and postal regulations. For mailers, using CASS-certified solutions is essential not just for operational efficiency but also for accessing bulk mailing discounts through automation-compatible mailing processes.

CASS plays a foundational role in modern direct mail and database hygiene, ensuring that address data is accurate, complete, and formatted for optimal processing by the USPS.