[wutwutwat]

You can also install some trusted certs and MITM the requests, replacing the content with whatever you'd like

Likely overkill for this use case, but no matter the client, you can in theory do whatever you want to any traffic up until the point it leaves your network.

[ImPostingOnHN]

what toolset do you use for on-the-fly translation?

ad-hoc code, or something with a more structured workflow, maybe?

this sounds like a fun thing to try, thanks for your time

[SoKamil]

Charles, Proxyman, or mitmproxy if you like open source + terminal would do the job.

[geoka9]

mitmproxy will even allow you to script the intercept/override behavior, which can be really handy.

[18172828286177]

See Burpsuite