It's an alternative to Sandstorm. We've made some different choices, like using full KVM VMs instead of Linux containers for apps. Portal also doesn't require that apps know much about Portal itself to be run as apps. They can use their own authentication or the single sign on system.

An unmodified Ubuntu cloud image is a valid (though basic) Portal app and can boot using CloudInit. Real world apps store data on the separate "user data" drive that is attached to all app VMs, which makes them upgradeable. And they almost always have a web interface for the user to interact with.

They can also use the Portal metadata service to interact with the system. But for the most part apps just receive raw TCP/IP traffic or proxied HTTP traffic and work normally.

We began working on Portal before Sandstorm was public, but I can tell you this is the first time I've been happy to see other people working on the same idea as myself. Decentralizing the internet is more of a mission than a competition.

Also, we expect to be able to run Sandstorm as a Portal app, so you could run many Sandstorm apps inside one VM, assuming they're okay with that.