MAC certification process is designed in cooperation with the mailing industry to evaluate USPS® manifest mailing products manufactured by vendors. MAC determines whether manifest mailing software accurately lists and calculates postage for identical- and/or nonidentical-weight permit imprint mailpieces according to the standards of the DMM®, IMM®, and Publication 401, Guide to the Manifest Mailing System reference manuals. Currently, this program is only available to software manufacturers who develop USPS single-piece itemized manifest mailing software for mailers seeking to generate manifested mailings. Mailers who develop manifest software for in-house use only and presorted mail/batch-listed manifest software products will be included in this program at a later date.

Although MAC evaluates and certifies USPS manifest mailing products, the program does not guarantee acceptance of customer mail prepared using MAC-certified software. However, MAC does provide national approval of computer-generated manifest listings, mailing statement facsimiles, and other USPS forms required for manifest mailings. Participation in this program is voluntary, and each user is responsible for proper software installation, use, and quality control maintenance.

MAC evaluates product accuracy by providing test data in mailpiece description files. Each record in the file represents a specific mailpiece and is described by attributes such as name and address of recipient, class of mail, processing category, weight in pounds and ounces, special service type, dollar value, identification number, and country code.

For each specific manifesting category tested, the USPS evaluates the documentation for listing, class, rate, and postage accuracy. In addition, the accuracy, format, and content of facsimile mailing statements and any other postal forms (where applicable) are evaluated. If the USPS determines that the manifest mailing product satisfies all applicable standards, the developer is issued a MAC certificate for the product in that category. Certification is valid for one year or until the end of the current cycle. Vendors whose products are certified in any or all categories receive a MAC certificate and have their name, address, and manifest mailing product name and version number published in the Postal Bulletin or a list of certified customers.