anything that could capture the traffic of another application outside of that application is likely gonna need super user privs. the ports it flows on need those to capture it, and running a program which could capture it also likely needs it.

that being said: more context would thus help. what application is making the request, and at what point do you expect to intercept or get that request? is that outside the same app or not?

edit: also, can you atleast set it up as root or does everything need to happen as user? (and the OS might also matter)

As noted in the ingress, the web browser is the primary application. It must work for an end-user lacking the technical facilities or even sufficient administrative access to install a resolver or edit the system's hosts file. A browser extension would be a great solution.