Fiber

Fiber is a Go web framework modeled after Express.js, built on fasthttp for high throughput. Routes, middleware, static files, template rendering, all with Express-like syntax but running on Go's fasthttp library instead of Node.js. It's consistently one of the fastest web frameworks in benchmarks.

The pitch is simple: Go's performance with an API that JavaScript developers already understand. If you're moving from Node to Go and don't want to learn a completely new routing paradigm, Fiber's learning curve is almost flat.

MIT. Fully free, no paid tier, no cloud service, no commercial edition.

The catch: Fiber uses fasthttp instead of Go's standard net/http library. That means some Go middleware and libraries that expect net/http won't work without adapters. The Go community has opinions about this; many prefer Chi or Echo because they stick to the standard library. If you care about long-term compatibility with the Go ecosystem, the fasthttp dependency is a real trade-off.