Fiddler - Fiddler is a debugging program for websites.
Browxy - Browxy is a web application that serves as an integrated development environment where you can write in coding languages, compile them or edit them.
Proxyman.io - Proxyman is a high-performance macOS app, which enables developers to view HTTP/HTTPS requests from apps and domains.
myCompiler - Run your favourite programming languages online
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.
CodeChef IDE - CodeChef IDE is a free online tool for developers helping them in writing codes and programs.