To get response data from the external API after it completes processing, the developer should expose an HTTP callback API in Mule and register it with the external system. This way, the external API can invoke the callback API with theresponse data when it is ready, instead of making the Mule application wait for a long time or poll for a response repeatedly. References:https://docs.mulesoft.com/mule -runtime/4.3/http-listener-ref#callback