Sorting and Processing

CASS Certification

CASS Certification (Coding Accuracy Support System) enables the United States Postal Service (USPS) to evaluate the accuracy of software that corrects and matches street addresses. CASS certification is offered to all mailers, service bureaus, and software vendors that would like the USPS to evaluate the quality of their address matching software and improve the accuracy of their ZIP + 4, carrier route, and five-digit coding.

NCOA (National Change of Address)

National Change of Address (NCOALink) is a secure dataset of approximately 160 million permanent change-of-address (COA) records consisting of the names and addresses of individuals, families and businesses who have filed a change-of-address with the USPS. It is maintained by the United States Postal Service and access to it is licensed to service providers and made available to mailers. The use of NCOALink is required in order to obtain bulk mail rates, as it minimizes the number of UAA (Undeliverable As Addressed) mailpieces saving the mailer money and reducing the USPS’s processing of this type of mail.

*We check NCOA up to 18 months


There are three ways to check your mailing list for duplicate addresses.

  • Household: One mailpiece per household
  • Last Name: One mailpiece per last name per address
  • Person: One mailpiece per person per address

*Our default deduping method is to only send one piece of mail per person at an address.

Mailing List

A sample mail list with headers and columns is attached for use. By providing your mail list in this format, it will ensure timely processing and reduce chances for error while working with your list.