Mail.dat vs. Mail.XML

Mail.dat® and Mail.XML are similar services for sending your mailing information electronically. But because these options are nearly identical, it can be difficult selecting the right service for your business needs. Here’s a guide to each service to help you decide which one will most benefit you.

What they have in common

• Mail.dat and Mail.XML each contain all the documentation you need to describe your mailing and populate all postal forms.

• Mail.dat and Mail.XML are industry standards maintained by IDEAlliance.

• In order to use either Mail.dat or Mail.XML with PostalOne!®, you will need to test your submissions in the Test Environment for Mailers (TEM) system.

• The layouts for Mail.dat and Mail.XML change periodically to account for changes in the industry and USPS regulations. PostalOne!supports up to two layouts of each at any one time.

• Both Mail.dat and Mail.XML satisfy the electronic documentation requirement for the Full-Service discount.

A few myths to dispel

• You need a Mail.dat license to use Mail.XML. False. In order to use Mail.XML, you do not also need Mail.dat. Mail.XML can be used as a standalone submission of your mailing paperwork. It can also be used to edit a Mail.dat submission.

• USPS is going to stop supporting Mail.dat. False. Mail.XML isn’t going to replace Mail.dat. Mail.dat is an established standard in the mailing industry and will continue to be used to communicate mailing structure and content to both USPS and third-party mail consolidators.

The Key Difference

Mail.dat is a file system

Mail.dat is a relational database that describes all parts of the mailing except the addresses themselves. It’s well known and supported by the mail industry, and is heavily used by logistics and mail consolidators. Because everything is contained in one file, it is easy to transfer everything to another computer by email or ftp. Mail.dat files can become rather large, and sending them may take extra time. Because Mail.dat contains all the possible information about your mailing, you can think of Mail.dat as an “encyclopedia” of your mailing.

Mail.XML is a communication system

Mail.XML is a way two computers can communicate. Bits of mailing information are described in XML messages. Together those messages become the content of your mailing. Mail.XML is relatively new and isn’t supported by all of the mailing industry yet. Storing Mail.XML is tricky; each communication is separate from the next. The smaller messages make communicating larger mailings faster. No extraneous data is included in the message. Because Mail.XML is a conversation about your mailing, you can think of Mail.XML as a series of emails about your mailing.

Which is right for me?

Talk with your downstream partners and your presort software vendor. Some of these companies haven’t made the switch to Mail.XML yet. But if you will be submitting your mailing data directly to PostalOne! and use a software product like Bulk Mailer, Mail.XML is the easier method to get started.