goproxy is described as 'Proxy is a high performance HTTP(S), websocket, TCP, UDP, Secure DNS, Socks5 proxy server, TLS. Chain-style proxies, NAT forwarding in different LAN, TCP/UDP port forwarding, SSH forwarding ,ipv4 and ipv6 supporting'. There are four alternatives to goproxy for Linux, BSD, Windows, Mac and Self-Hosted solutions. The best alternative is nginx, which is both free and Open Source. Other great apps like goproxy are Haproxy (Free, Open Source), Envoy Proxy (Free, Open Source) and gobetween (Free, Open Source).
nginx [engine x] is a HTTP and reverse proxy server, as well as a mail proxy server written by Igor Sysoev. It has been running for more than five years on many heavily loaded Russian sites including Rambler (RamblerMedia.com).