Freebli was a fun project to work on, built entirely as a backend-less app. It uses React, the Context API, Hooks, and Google Firestore.
It was a great way of exploring effective use of github and shared repos, the ease and power of Google Firebase, and integrating different libraries into a unified app
The learning curve on using Firebase (both Firestore and Firebase Storage) was surprisingly painless, but getting the auth components working nicely was challenging. Authentication can be simple, but defining users and roles requires some careful pre-planning.