CASS (Coding Accuracy Support System) Certification was Developed by the United States Postal Service (USPS) to test the accuracy of address-matching software
CASS(Coding Accuracy Support System) Certification is program that was developed by the USPS to test the accuracy of address-matching software and improve the accuracy of postal coding, such as ZIP+4 Code®, carrier route and 5-digit ZIP Code coding.

Authoritative Evaluation of Address-Matching Software

Melissa is an official CASS Certified USPS® vendor – but what does that mean? Coding Accuracy Support System (CASS) Certification is a program that was developed by the USPS to test the accuracy of address-matching software and improve the accuracy of postal coding, such as ZIP+4 Code®, carrier route and 5-digit ZIP Code coding. The USPS had created it to incentivize higher quality address processing in order to;

  • Reduce undeliverable mail
  • Reduce unsortable mail
  • Reduce mail that requires extra effort by postal workers to reach the intended address

CASS Certification has since become a benchmark for software providers, developers, service bureaus, commercial mailers and more to verify the quality of their address matching and correction capabilities. This enables mailers to compare and measure the effectiveness of internally written or commercially available address matching software packages.

What is the CASS Certification Process?

CASS Certification has two stages (Stage I and Stage II). Stage I is an optional, self-administered test for developers to use as a measurement or diagnosis of address matching software before proceeding to Stage II. This test is not graded by the USPS, so it provides useful insight into the software’s performance as well as deficiencies prior to certification testing.

Stage II is the test that evaluates the address matching software to receive certification. The software must reach a specified percentage of accuracy in order to receive CASS Certification. After achieving the required accuracy, the provider then becomes certified and must renew their certification annually to meet current requirements.

What Can CASS Certified™ Software do?

CASS Certified software can range in capabilities, but generally they can correct misspellings, standardize to USPS guidelines and add missing components to address elements. These elements include street names, city names, ZIP and ZIP+4 Codes, and street suffixes.

Why Choose CASS Certified Software?

CASS Certification is an indication of higher accuracy and thus higher quality address processing. Improved address accuracy directly corresponds to higher response and return and lower cost and waste, among a slew of other benefits for any mailer. Among those benefits, the USPS also requires mailing lists to be processed by CASS Certified software in order to qualify for automation rates and other mailing discounts.

Get Started with Address Verification

Find the right CASS Certified Address Verification tool for your needs. Plus, see how Melissa’s address engine goes above and beyond the USPS and why we’re known in the industry as the Address Experts.

250+ Countries & Territories
1,000,555,787+ Addresses Verified
40 Years
10,000+ Customers Worldwide