USPS Glossary
CASS
Coding Accuracy Support System — USPS standard for validating and standardizing mailing addresses.
Full definition
CASS is administered by USPS. Vendors run customer lists through CASS-certified software before printing to confirm each address exists, standardize the formatting to USPS spec, add ZIP+4 codes, and flag undeliverable entries. Mailings on CASS-cleaned lists qualify for better postage rates and have dramatically lower bounce rates.
Related terms
- NCOA →
National Change of Address — USPS database of recent moves used to update mailing lists before print.
- EDDM →
Every Door Direct Mail — USPS service that delivers your mail to every household on a selected carrier route.
- EDDM Retail Indicia →
The pre-printed postage marking on EDDM mail that replaces a stamp.
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