The tldr is yes, but not sure about which part will be open source and which part will remain private, and when.

The API & web app components will definitely remain private, but the CLI tool itself can be open source.

If you run ‘paper config’ today, you will still see that you can configure the “sync url” - basically that allows you to sync your content to your own hosting provider.

I spent non-trivial thought on this topic during development, but then ended up with a conclusion that I should just make it private for now to speed up feature development. Otherwise I would need to think really hard on the interface & contract design.