nginx reverse proxy

gistfile1.txt

 server {
        server_name domain.xyz;

        location / {
                proxy_pass http://localhost:3333;
                proxy_http_version 1.1;
                proxy_set_header Upgrade $http_upgrade;
                proxy_set_header Connection 'upgrade';
                proxy_set_header Host $host;
                proxy_cache_bypass $http_upgrade;

                add_header Access-Control-Allow-Origin "domain.xyz";

        }
 }