Google Chrome Developer Tools - Get started with Google Chrome's built-in web developer tools.
HTTP Debugger - Debug HTTP API calls to a back-end and between back-ends. Easy of use, clean UI, and short ramp-up time. Not a proxy, no network issues!
Omnibug - Omnibug is a plugin for the Google Chrome and Mozilla Firefox browsers to ease developing and...
HTTP Header Live - Displays the HTTP header. Edit it and send it.
Fiddler - Fiddler is a debugging program for websites.
HttpRequester - Download HttpRequester for free.