mitmproxy/doc-src/features/reverseproxy.html

In reverse proxy mode, mitmproxy acts as a standard HTTP server and forwards
all requests to the specified upstream server. Note that the displayed URL for
flows in this mode will use the value of the __Host__ header field from the
request, not the reverse proxy server.


<table class="table">
    <tbody>
        <tr>
            <th width="20%">command-line</th> <td>-P http[s]://hostname[:port]</td>
        </tr>
        <tr>
            <th>mitmproxy shortcut</th> <td><b>P</b></td>
        </tr>
    </tbody>
</table>