StockFlow ERP

StockFlow ERP is a comprehensive production-grade solution designed to handle core business operations for a wholesale/distribution enterprise. Built as a full-stack developer case study, it showcases REST API design, complex database modeling, role-based authentication, and real inventory business logic wrapped in a modern SaaS-style UI built with Tailwind CSS v4.

The system manages customers, products, inventory, sales challans, and follow-up activities for internal teams such as Sales, Warehouse, and Accounts — each with role-specific access.

• Frontend: React + TypeScript + Vite — fast HMR during development; React Router for multi-page navigation.
• Styling: Tailwind CSS v4 for a consistent, responsive SaaS design system.
• Backend: Node.js + Express.js (TypeScript) — RESTful API with modular routes, controllers, services, and middleware layers.
• Database & ORM: PostgreSQL with Prisma ORM — type-safe, migration-driven schema management.
• Auth & Validation: JWT Authentication, Zod schema validation on all API inputs, role-based middleware on every protected route.
• Deployment: Vercel (Frontend), Render (Backend), GitHub Actions CI/CD pipeline.

The system implements JWT-based authentication with distinct role access levels. A single requireRole() middleware guards every protected route, ensuring each team sees only what's relevant to them:

• Admin: Full access — users, products, customers, challans, reports.
• Sales: Manage customers and create/view challans.
• Warehouse: View and manage inventory and stock movements.
• Accounts: View challans, financial summaries, and reports.

The inventory module handles complete product lifecycle management with built-in safeguards:

• Product & SKU Management: Add, edit, and categorize products with full SKU assignment.
• Real-Time Stock Tracking: Live stock levels with configurable minimum stock alerts for low inventory warnings.
• Immutable Movement Log: Every stock change (IN/OUT) creates a timestamped, paginated audit log — capturing the product, quantity, reason, responsible user, and timestamp.

The challan system is the core business workflow of StockFlow ERP, requiring precise implementation of business rules:

• Sequential Numbering: Challans are auto-assigned a sequential ID in the format CH-YYYY-NNNNN, auto-incremented at the database level to prevent duplicates.
• Draft → Confirmed → Cancelled: Challans go through a state machine; stock is only deducted on confirmation.
• Product Snapshot: Product name, SKU, unit price, and quantity are snapshotted at time of sale in a JSONB column — preserving historical accuracy even if product details change later.

• GitHub Actions: A CI pipeline (.github/workflows/ci.yml) runs on every push — linting, type-checking, and building both frontend and backend to catch regressions early.
• Vercel: Frontend is deployed with VITE_API_URL pointing to the production backend — zero config, instant CDN distribution.
• Render: Backend runs with environment variables for database, JWT secret, and CORS origin — npx prisma migrate deploy runs automatically on startup to keep schema in sync.