In their own benchmark, Vapor is about as quick Gin, written in Go.
Looking at Techempower's latest web framework comparison [0], we see that Gin reaches only 27% the requests per second of the quickest tested framework, and 28% of the quickest framework written in Go.
[0] http://www.techempower.com/benchmarks/#section=data-r15&hw=p...
That test says nothing about real world performance though, that's true. The db read and write benchmarks are more useful.
When Swift was first released as open source the potential for using it server-side felt really intriguing, it's great to see how far along the community has come in such a fairly short time!
I simplify it as an easier Rust that comes with an official REPL.