Lanternfish

Lanternfish is the smallest useful thing on top of Next.js and Supabase. You get email, Google and GitHub sign-in through Supabase Auth, row-level security policies already written for a profiles and projects table, Stripe Checkout with a webhook that syncs subscription status, and a settings page for account deletion. Emails go through Resend with plain HTML templates.

Its opinion is that the database should enforce access, so nearly every permission check lives in SQL policies rather than in route handlers. That keeps the TypeScript lean but means you will be writing Postgres. The limitation: there are no teams or organizations at all. Adding them means reworking the policies, which the maintainer says is out of scope.