This is very cool! I will say though, my spidey senses kick in when looking at stuff like this, and make me wonder about how much I'm going to get vendored in here. Could I use it develop a site off fly.io? If the answer is no, then I'd say this is cool and I think useful for people who need something quick and simple and out of the box, but not something I would ever use on a serious production project.

The answer is yes. What would you say then?

There’s a “clone Git repo” thing in the left side bar, use that to clone the project locally, mix deps.get, mix phx.serve and you’re up. You can deploy this anywhere you want.

It’s just producing Elixir/Phoenix code that is stored in GitHub and can be deployed anywhere.