Interesting timing — I made a similar move recently but coming from a different stack: Firebase for auth + PostgreSQL on Azure for data. The Azure Postgres cost was the first trigger, but what really sold me on Supabase was being able to run the entire stack locally during development, including auth. With Firebase Auth you can't really replicate that locally. The RLS simplicity was also a big factor. Writing Firestore security rules always felt like a separate discipline. With Supabase it's just SQL policies, same language I'm already thinking in. One thing I haven't seen mentioned: the open-source aspect matters a lot for long-term confidence. If Supabase changes pricing or direction, self-hosting is a real option.
Yes I definitely need to test the Marionette package … widget tests are really slow and unstable