MATHEUSBATISTA

FinCore

FinCore: a personal finance web application (Brazilian context) developed entirely (frontend and backend), which evolved from an approved prototype to a production-level product. The system covers the complete financial cycle: installment expenses, shared expense management (with per-person settlement), card invoices with configurable competence, transfers, budgets, goals, future balance projection, and exportable accounting reports (PDF and CSV). The stack includes Next.js 16 (App Router, React Server Components, and Server Actions) with React 19 and strict TypeScript, Drizzle ORM over PostgreSQL via Supabase (Auth with SSR), Tailwind CSS v4, React Hook Form with Zod, TanStack Query and Zustand, and next-intl for the UI in pt-BR. The architecture adopts Clean Architecture in 4 layers, with a pure financial domain (all monetary values in integer cents, without floating point) and multi-user isolation via Row-Level Security in Postgres. Quality is guaranteed by Vitest with property tests (fast-check), a 95% coverage gate in the domain, Biome, Conventional Commits, and CI on GitHub Actions, with continuous deployment on Vercel. The result is a financial application that ensures banking-level accounting accuracy and multi-user security, validated by automated tests with each delivery.