This is a production-oriented full-stack SaaS starter kit (not a data/research project). It is a monorepo template pairing a Next.js web app (landing page, auth flow, account dashboard, marketing sections) with a Flutter cross-platform app (iOS/Android/macOS/Windows/Linux/web) on top of a shared Supabase backend. The backend is a Postgres schema (users, customers, products, prices, subscriptions, invoices) protected by row-level security, plus Deno edge functions that orchestrate Stripe Checkout sessions and process Stripe webhooks. PostHog handles analytics on both frontends, Loops.so handles transactional email, and an optional Monero cryptocurrency payment variant can be toggled in via patch scripts, giving the template two billing backends.