Does Appian have an HTTP "Listener" that an external application can s

Following up on this request as I have this question and the linked post is no longer available. Hoping to push this up. 

Reopening an 11 years old conversation?

To expose functionality to the external world, we create web APIs.

https://docs.appian.com/suite/help/24.1/Web_APIs.html

Hi Steven, Yes I am aware and have used web APIs in Appian applications.

If you read the initial request its specifically around functionality for an event listener. In which an endpoint is exposed for external systems to send asynchronous updates/statuses. These endpoints are not meant to send data externally (or receive updates to records), but receive calls from an external system when triggered by an event to log an occurrence. 

Yeah, that is exactly what web API objects in Appian are meant to do. Some other system sends something to Appian.

Maybe you can describe your use case in more detail.