Mitmproxy -w - how to include results

I get requests and parameters, but not the results (json etc) - how can I include them into my outfile ?

Each flow is stored in the out file. If a flow has the response, it will be there in the out file.

I can see the output using charles proxy, but mitmproxy does not show it. If I search in the out-file, the json output fields are not found…

How exactly are you searching the out file?
mitmproxy uses tnetstrings not json

I open the out file in a text editor and do simple text search…

If the server responds with gzipped data (compressed on the fly) then MITMProxy will store it that way. If you specify the -z or --anticomp command line argument, it tells servers that it doesn’t want gzipped data so you should get the raw data instead.

That works - thanks… One final question, the CERTICATE is that client sent to server, or certificate received from the server ?

That is the certificate received from the server.