Monitor public websites and private homelab services from a native iPhone app — no port forwarding needed. Free: HTTP/HTTPS, TCP, SSL & domain expiry via cloud. Includes a public status page. Pro: Deploy a 6MB Docker agent (Synology, QNAP, Unraid, Raspberry Pi, Proxmox, Linux). Monitor internal services on private IPs — outbound HTTPS only, your firewall stays closed. Push notifications on both plans.