Charles Proxy - HTTP proxy / HTTP monitor / Reverse Proxy
Surge for Mac - Advanced Web Debugging Proxy for Mac & iOS
Wireshark - Wireshark is a network protocol analyzer for Unix and Windows. It lets you capture and interactively browse the traffic running on a computer network.
Weer - A HTTP protocol debugger with Chrome DevTools frontend interface
Postman - The Collaboration Platform for API Development
Proxyman.io - Proxyman is a high-performance macOS app, which enables developers to view HTTP/HTTPS requests from apps and domains.