The Zone Analysis Program (ZAP) provides a common platform to measure the quality of Zone assignments, ensuring the accuracy of postage rates claimed in accordance with requirements set forth in the DMM® reference manual. Software products that successfully complete the ZAP testing process are identified as ZAP approved.

The United States Postal Service provides Zone Chart information in a electronic format to assist mailers in developing software that provides accurate zone assignment to mail. To qualify for ZAP approval, the software developer must subscribe to the electronic National Zone Chart Matrix, and their software must incorporate the most recent version of the National Zone Chart Matrix.

Publishers who use ZAP-approved software no longer have to go through the zone analysis during their annual Postage Payment Review. After ZAP approval, the publisher's Postal forms and qualification reports will indicate 'ZAP' and the Zone Chart Matrix date of the data used.

The most current Zone Chart matrix must be used at all times to qualify for ZAP approval. For more information, contact the National Customer Support Center at 1-800-331-5746.