USPS-certified address matching software that standardizes addresses and appends ZIP+4, carrier route, and delivery-point data when available.
CASS
Coding Accuracy Support System
Addressing & Lists
Definition reviewed 2026-07-24. Plavidian reference, written from the USPS Domestic Mail Manual. Final mail classification, postage, and preparation are confirmed after list processing and production review.
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Ask the Plavidian Mail Expert™ for an answer grounded in the USPS Domestic Mail Manual, or send us the job and we will confirm the preparation before you print.