Portmap.io is described as 'Port forwarding service for exposing your local PC to Internet from behind firewall or without real IP address. Uses OpenVPN or SSH encrypted tunnel from localhost to Portmap.io' and is an app in the development category. There are more than 25 alternatives to Portmap.io for a variety of platforms, including Linux, Mac, Windows, Self-Hosted and Android apps. The best Portmap.io alternative is ngrok, which is free. Other great apps like Portmap.io are tunnl.gg, LocaltoNet.com, Rathole and sish.