upstream app_backend { server 127.0.0.1:3000; keepalive 16; }
server {
  listen 80; server_name app.example.test;
  location / {
    proxy_http_version 1.1;
    proxy_set_header Host $host;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header X-Forwarded-Proto $scheme;
    proxy_connect_timeout 3s; proxy_read_timeout 30s;
    proxy_pass http://app_backend;
  }
}