That depends entirely on the capabilities of the app that is to receive the notification. If it's supported, Amazon SQS is particularly suited for such a thing. If not, then there's the Push subscriber that's fairly accessible, in particular if your app has a REST-like API.

Here's a list of all the subscriber technologies supported by FME Server, hopefully one of them is supported by your third party app: https://docs.safe.com/fme/html/FME_Server_Documentation/Content/ReferenceManual/Subscribers.htm

@david_r

what we are trying to push any transaction from different system (ex. building licenses, permits license ..ext ) to a remote central data warehouse by building topics for each type of information and we subscribe to those topics in order to push data to the destination as soon as it triggered.