CASS-CertificationCass certification means that we meet all of the stringent USPS accuracy requirements. This translates into savings for our clients because we are able to clean up, standardize and verify as deliverable all of the addresses that you provide. As a result of being CASS certified USPS will reward you by allowing you to pay a lower price for postage. This process certifies to the post office that your mailing has been processed by our address verification service.