# DeliveryResponse Overview

The DeliveryResponse allows clients to receive status updates from the delivery service at the endpoint they have specified on the request.

## External Callback Overview

Users supply the Callback URL, Username, and Password with the Deliver API to integrate with IEDocService in Expere Document Services.

The delivery service uses IDeliveryResponse to provide a series of status messages; see below. To use callbacks with Deliver API's, integrators should implement "FulfillmentDeliveryResponse" for "IDeliveryResponse."

## Status Messages

The Callback will display the following status and details (separated by the"/" in the list below):

- Processing/Processing
- Printed/Printed
- Mailed/Mailed
- Delivery Attempt Made/Status Message
- Delivered/Status Message
- Undelivered/Status Message
- Returned/Status Message
- USPSStatus/Status Message
- Error/Error Message
- Tracking Number/Tracking ID
- Return Receipt/