Very nice!

On the same note, I wrote a program to generate Python code (requests) from a HAR capture: https://github.com/louisabraham/har2requests

I think using HAR captures is simpler for the end user than spawning mitmproxy as they don't require any installation and are extracted from the network tab of the browser devtools. Is there a reason why you didn't use them?

EDIT: I realized that mitmproxy can also get traffic from other devices like phones. Very cool project, I will think about modifying mine to support mitmproxy captures!