This is a shameless plug, but I built Swift Cloud to help people build scalable backends in Swift: https://swift.cloud

Behind the scenes we compile Swift to WASM and deploy to Fastly's edge network, Compute@Edge. At my day job we are using this in production and serving thousands of requests per second on our Swift app. Overall it's a lot of fun to deploy Swift on server, but the developer UX still leaves a lot to be desired. Running and testing locally is still non-trivial.