socat - socat is a relay for bidirectional data transfer between two independent data channels.
Fiddler - Fiddler is a debugging program for websites.
Simple Port Forwarding - Simple Port Forwarding works with WebPages and not directly with your router.
Proxyman.io - Proxyman is a high-performance macOS app, which enables developers to view HTTP/HTTPS requests from apps and domains.
PortMapper - Do you need to map a specific TCP or UDP port on your machine to another port on another machine?
HTTP Toolkit - Beautiful, cross-platform & open-source tools to debug, test & build with HTTP(S). One-click setup for browsers, servers, Android, CLI tools, scripts and more.