Man in the Middle is described as 'Modify requests, inject JavaScript and CSS into pages' and is a userscript manager in the web browsers category. There are more than 10 alternatives to Man in the Middle for a variety of platforms, including Google Chrome, Mozilla Firefox, Microsoft Edge, Web-based and Windows apps. The best Man in the Middle alternative is Greasemonkey, which is both free and Open Source. Other great apps like Man in the Middle are Violentmonkey, Stylus, Tampermonkey and Random User-Agent.