Is it possible to rewrite requests/responses?

[postmodern]

Is it possible to rewrite network requests / responses before they are sent out or processed by the browser?

[route]

I think you are looking for https://github.com/rubycdp/ferrum#interceptoptions especially request.respond part

[postmodern]

Will that rewrite the request that is sent to the web server or override the response that the browser receives?

[route]

That's for response

[route]

For request there's a way with standard CDP Fetch.continueRequest

You can override: url | method | postData | headers

Here's an example in tests 5271866