nginx.conf

http {
    server {
        listen 80;

        location / {
            root /var/www/;
            try_files /index.html =404;
        }
        location /prefix/ {
            # Nginx doesn't escape URIs for some reason when using the
            # default strip thingy. This works around that by manually
            # rewriting and using the URI.
            # See https://stackoverflow.com/questions/28684300/nginx-pass-proxy-subdirectory-without-url-decoding/37584637#37584637
            rewrite ^ $request_uri;
            rewrite ^/prefix/(.*)$ /$1 break;
            return 403; # only if it didn't match
            proxy_pass http://localhost:10240$uri;
        }
        location /vs/ {
            # This path isn't prefixed for whatever reason
            proxy_pass http://localhost:10240;
        }
    }
}

events {}