upstream api {
        least_conn;
        server 127.0.0.1:[YOUR_PORT] max_fails=1 fail_timeout=2s;
        server 127.0.0.1:[YOUR_PORT] max_fails=1 fail_timeout=2s;
        server 127.0.0.1:[YOUR_PORT] max_fails=1 fail_timeout=2s;
    }

    server {
        server_name [YOUR_DOMAIN];
        listen 80;
        location / {

            add_header 'Access-Control-Allow-Origin' '*';
            add_header 'Access-Control-Allow_Credentials' 'true';
            add_header 'Access-Control-Allow-Headers' 'Accept,Origin,Keep-Alive,User-Agent,Cache-Control,Content-Type';
            add_header 'Access-Control-Allow-Methods' 'GET,POST,OPTIONS,PUT,DELETE,PATCH';

            proxy_intercept_errors on;
            proxy_connect_timeout                   5s;
            proxy_send_timeout                      20s;
            proxy_read_timeout                      20s;

            proxy_pass http://api;
        }
    }