Mitmproxy is a free and open-source interactive HTTPS proxy.

It is a swiss-army knife for debugging, testing, privacy measurements, and penetration testing. It can intercept, inspect, modify and replay web traffic such as HTTP/1, HTTP/2, WebSockets, or any other SSL/TLS-protected protocols. You can prettify and decode messages …

When you need archive sites, for research, there's often no better a tool than Wget. Wget is available for almost all platforms. If you don't already have access to Wget or have never used it before check out my Wget OS tutorials: Using Wget on Linux. Using Wget on OSX …