oh, just saw you said you're making one, I like to use mitmproxy: https://mitmproxy.org or SOCKS through ssh, but technically you can use a few different methods to make it work.
https://en.wikipedia.org/wiki/Proxy_server#Implementations_of_proxies
For directly visit this IP and rehost this page, with minimal or no intercepting, nginx's proxy_pass would be a straightforward way: https://www.reddit.com/r/nginx/comments/k1chxw/comment/gdnbe8l/ which afaik just fetches the page, replaces a few strings, and re-serves it.