Google Chrome Developer Tools - Get started with Google Chrome's built-in web developer tools.
Fiddler - Fiddler is a debugging program for websites.
Firefox Developer Tools - Examine, edit, and debug HTML, CSS, and JavaScript on the desktop and on mobile.
Proxyman.io - Proxyman is a high-performance macOS app, which enables developers to view HTTP/HTTPS requests from apps and domains.
Postman - The Collaboration Platform for API Development
mitmproxy - mitmproxy is an SSL-capable man-in-the-middle proxy for HTTP.