fasthttp

Benchmarks show fasthttp servers are up to 6x faster and clients up to 4x faster than net/http, with zero allocations in hot paths reducing GC pressure.

Successfully serves over 1.5 million concurrent keep-alive connections per physical server in production, as noted in the README from VertaMedia.

Allows setting headers and writing response body in any order, unlike net/http's sequential restrictions, providing more control for advanced use cases.

Encourages zero-allocation designs with unsafe helpers for byte-string conversions and tricks like reusing []byte buffers, minimizing memory overhead.