Frappe Books is a full-featured, offline-first desktop accounting and inventory management application built with Electron, Vue 3, and a custom ORM framework (fyo) on top of SQLite. It supports double-entry bookkeeping, invoicing (Sales/Purchase/Returns), payment processing, stock management (batches, serial numbers, FIFO valuation), Point of Sale (classic and modern layouts), financial reports (Balance Sheet, P&L, Trial Balance, General Ledger, GST reports), loyalty programs, pricing rules, coupon codes, and multi-currency. The architecture is schema-driven: JSON schema files define document structures, and model classes add business logic via formulas, validations, and lifecycle hooks. The backend runs in the Electron main process and exposes IPC APIs for file operations, database access, and auto-updates. The frontend is a reactive Vue 3 SPA with a comprehensive component library. Regional support (India, Switzerland) is implemented through model overrides and schema extensions. The codebase demonstrates strong engineering practices with a layered architecture, but the custom framework introduces some coupling. It is actively maintained with CI/CD, automated tests, and regular patches.