We did a write-up on the tech stack and some of the approaches we considered for sharing code between our Platform and the Self-Hosted versions here: https://supabase.com/blog/2021/11/30/supabase-studio
We aim to get these to parity with each other, excepting some billing/server management features.
A big shout out to Sentry who do served as a good model for us (https://develop.sentry.dev/sentry-vs-getsentry/)