I've built a few simple apps running on Linux that have worked great.

Check out Zewo[1]. They've been doing a lot of great work to make Swift 3.0 on the server work really well. Also, check out VeniceX[2] for concurrency and Open Swift[3] for cross project standards[3].

[1]: https://github.com/Zewo/Zewo/ [2]: https://github.com/VeniceX/Venice [3]: https://github.com/open-swift/docs