The MessageMedia Messages API provides a number of endpoints for building powerful two-way messaging applications. The Messages API provides access to three main resources:
1) Messages - Messages delivered from an application to a handset.
2) Delivery Reports - Real time reports on the delivery status of a message. As a message is processed, it's status may change several times before it is finally delivered to a handset.
3) Replies - Messages sent from a handset to an application. These messages are typically a reply to a previously sent message.