TinyWall - Lightweight and non-intrusive firewall
Fiddler - Fiddler is a debugging program for websites.
Windows Firewall Control - Windows Firewall Control is not the built in firewall system in the Windows operating systems.
Proxyman.io - Proxyman is a high-performance macOS app, which enables developers to view HTTP/HTTPS requests from apps and domains.
Windows 10 Firewall Control - Windows 10 Firewall Control: simple and exhaustive solution for applications network activity controlling and monitoring.
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.