About Mail.XML Messaging
Mail.XML employs Web Services messaging techonology. As such, it follows a request/response messaging structure. That means that for every request message coming from one party, there is a response message from the recieving party.
There are a number of message types within Mail.XML. These include:
- Delivery/Delivery Response: USPS delivers mailing data such as start-the-clock to a customer and the customer verifies receipt of the delivery.
- Notification/Notification Response: USPS delivers a notification that mailing data such as start-the-clock is available for a customer to pick up and the customer verifies receipt of the notification.
- Query Request/Query Response: One party queries information from a second party and the second party either returns the information or returns an error code. The query may be used to "pick up" data specified in a notification (see above)
- **Request/**Response: Generic request/response messages are used for general business communications. The request is often to "create," "update," or "cancel" appointments or content.
Some examples of Mail.XML messages include:
- Full Service Address Correction Delivery / Delivery Response
- Full Service Nixie Detail Delivery / Delivery Response
- By-For Conflict Query Request / By-For Conflict Query Response
- Delivery Appt Query Request / Delivery Appt Query Response
- Delivery Appt Create Request / Delivery Appt Create Response
- Delivery Appt Cancel Request / Delivery Appt Cancel Response
- Close Mailing Group Request / Close Mailing Group Response
- Consolidated Periodical Statement Create Request / Consolidated Periodical Statement Create Response
With the development of MailXML 9.0, the messages have been divided into 6 groupings:
- Transportation Messages
- Mailing Messages
- Data Distribution Messages
- Identification Messages
- Supply Chain Messages
- System Messages


