The front end is built with react, backend is using using prisma and Apollo Server.

There is no plugin system currently, but something I'm open to! I think that could be a great way to let people make Adventurekeep into what they really want it to be.

I do have an internal roadmap. If there's broader interest, I could clean it up and make it a public Trello board.

The application is not currently open source. But that could change if I were to introduce something akin to a plugin system.

Thanks for the questions!