The Coding Accuracy Support System, or CASS™, is a system designed to improve the accuracy of the address and ZIP Code™ that appears on each item in a bulk mailing.
Mailings that are CASS™ certified are eligible for certain bulk mail postage discounts. In order to become CASS™ certified, the mailing list must be run through a software program approved by the USPS®.
Any software that correctly formats addresses and includes accurate ZIP + 4® is eligible for CASS™ certification, but to qualify it must achieve:
It is important to note that CASS™ certification only handles the proper ZIP Code™, not primary or secondary information. Therefore, a CASS™ certified piece of mail may arrive in the correct city, state and ZIP Code™ but not at the correct residence because of a nonexistent house or apartment number.