I'm implementing (for the first time) a web service client in Swift using the Combine framework. For a method that makes a single call to a web service and then closes the connection, what is considered best practice – to return a Future or a Publisher? func getSomeThing() -> Future<SomeThing...> { } func getSomeThing() -> AnyPublisher<SomeThing...> { } In Flutter, a single async value would be a "Future" and multiple async values would be a "Stream". In the WWDC 2019 talk: "Introducing Combine" Apple presents a slide that hints at Futures as the async version of a single sync value. And Publishers as the async version of sync arrays. I understand that Futures in fact are Publishers. And that there may be some subtle technical nuances to consider (greedy/lazy etc). But thinking about the communicated intent, returning a Future seems to indicate a one hit wonder pipeline better than returning an AnyPublisher. But returning a Publisher seems easier and more in line with the framework, since it's pretty easy to eraseToAnyPublisher, for example from an URLSession.DataTaskPublisher, and just return that object. Mapping a DataTaskPublisher pipeline to a Future dosen't seem to be straight forward at all. Any best practice advise would be appreciated.