If I could give one recommendation here: fully document the paid features. You have zero docs that I could find on how you do authentication, authorization, subscriptions, or multi-tenancy. These are going to be the main reasons for people to purchase your boilerplate, yet there's no code examples to be found. I don't want to read how to build yet another todo app. I want to read about how to use your paid features. The todo app doesn't touch on any of your paid features.
As a buyer, I don't want to know what the definition of authentication is. I know what it is. I want to see how easy your implementation is to use vs the myriad of authz/authn packages on npm so that I can determine if your boilerplate will save me time.
Also, volca-core needs a LICENSE. :)
