BuanaBooks

BuanaBooks is a full-stack ERP system I'm building from scratch to replace the previous system for CV Hafidz Buana Abadi, a plywood manufacturing company. The platform handles end-to-end accounting workflows including chart of accounts management, contact/master data, general ledger, journal entries, and financial reporting, with all interfaces localized in Bahasa Indonesia and carefully replicated from the previous systems to ensure zero staff retraining. Built as a TypeScript monorepo using Turborepo and pnpm workspaces, the stack combines Next.js 16 with Turbopack, React 19, and Tailwind CSS v4 on the frontend, tRPC v11 for end-to-end type safety, Prisma 6 with PostgreSQL 16 for the data layer, and NextAuth v5 with bcrypt-hashed credentials and account lockout for authentication. Key engineering decisions include enforcing Decimal(19,4) for all monetary fields, immutable posted journals with reversal-only corrections, soft deletes on master data, a customizable dashboard with 28 draggable/resizable widgets via react-grid-layout v2, and a full COA migration pipeline that preserved all 281 accounts — including 43 monthly VAT accounts — from the client's existing data export.