tinytcp is a high-performance, zero-allocation TCP server in Go. It wraps around the standard net library to provide a sane API for quick prototyping. Major features include:

• No external dependencies.
• No memory allocations on critical paths, all the important objects and buffers are pooled.
• Automated packet extraction with no memory allocations (see LengthPrefixedFraming or SplitBySeparator).
• Full customization of connection handling process. By default, the sever starts a new goroutine for each connection, (GoroutinePerConnection strategy), but this can be changed.
• Metrics collection for both the server and each connected client separately (optional Prometheus binding).
• Support for tcp, tcp4, tcp6 and unix listeners.

go get github.com/mkorman9/tinytcp

package main

import (
	"fmt"
	"github.com/mkorman9/tinytcp"
)

func main() {
	server := tinytcp.NewServer("0.0.0.0:7000")

	server.OnStart(func() {
		fmt.Printf("Server started on: %d\n", server.Port())
	})

	server.ForkingStrategy(tinytcp.GoroutinePerConnection(serve))

	if err := tinytcp.StartAndBlock(server); err != nil {
		fmt.Printf("Error while starting: %v\n", err)
	}
}

func serve(socket *tinytcp.Socket) {
	socket.Write([]byte("Hello world!"))
}

GOMAXPROCS=1

$ GOMAXPROCS=1 go test ./... -bench=. -benchmem
BenchmarkSingleClient             728698              1582 ns/op               0 B/op          0 allocs/op
BenchmarkConcurrentClients        757249              1577 ns/op               0 B/op          0 allocs/op

GOMAXPROCS=8

$ GOMAXPROCS=8 go test ./... -bench=. -benchmem
BenchmarkSingleClient-8           615766              1838 ns/op               0 B/op          0 allocs/op
BenchmarkConcurrentClients-8     4523785               273.7 ns/op             0 B/op          0 allocs/op