hummingbird

Hummingbird is a lightweight web framework for writing servers in Swift, the language most people know from iPhone apps. It gives you a router, middleware, request and response encoding, TLS and HTTP/2 on top of SwiftNIO, Apple's networking engine, and pulls in as few dependencies as it can. Apache 2.0, free.

You add it as a Swift package and deploy the result like any server binary. The core stays small on purpose. Authentication, WebSockets, Redis, job queues, Mustache templates, the Fluent ORM and AWS Lambda support are separate official packages you add when you need them. The current release needs Swift 6.1 tooling.

Swift developers who want to share code and types between an iOS app and its backend are the natural fit. Vapor is the bigger, batteries-included option with a larger community. Pick Hummingbird when you want to assemble only the pieces you use. Every team size pays the same, nothing.

The catch is Swift on the server itself. Hosting guides, libraries and hiring pools are a fraction of what Node, Go or Python offer, so you will do more of the deployment plumbing yourself. Great framework, niche ecosystem.