One of the main use cases for server-side Swift is building REST APIs. Interacting with network data is a key function of almost any app, and until now, that server-side component had to be built by someone else with the relevant server-side skills. Alternatively, it required an app developer to frequently switch between programming languages and development environments to build both the client-side and the server-side code of an app.
Swift on the server opens the possibility for a developer to work on everything involved in the app, and move seamlessly between the client side and server side.
Much has been done by the Swift team to encourage the use of Swift on the server, including creating a new networking framework for running servers. This new framework is called SwiftNIO and is available open-sourced on GitHub: github.com/apple/swift-nio.
This framework is quite low-level, and a number of higher-level frameworks exist to make creating...