# Callback Overview

Callback operations allow Expere Document Services (EDS) to call into the client system and submit information to the client in a request to a provided URL in a previous Asynchronous Request. This is referred to as a push where the service submits a request containing the desired information directly to a callback listener at the designated URL. This communication method requires the setup of an application to receive soap Requests from EDS.

Calling methods using a callback communication allow the calling application to continue processing other requests while a request is being processed by EDS; the platform then initiates a call to the provided URL in order to push information to the listener. The calling application (client) must explicitly tell the platform (receiver of the call) what to do with the result, by configuring the callback listener URL and credentials in the initial request.

CallbackHandler and DeliveryResponse contain more information on integrating with each interface.