AI-Powered OCR Challan Processing & Automated Billing System

Overview: We are seeking an experienced full-stack developer or agency to build an AI-powered OCR Challan Processing & Automated Billing System. The solution will automatically read uploaded challan images/PDFs, extract relevant data, group them shop-wise, and trigger automatic PDF invoice generation once a shop reaches 200 processed challans. Key Features & Modules: Authentication: Secure user login with JWT and password protection. OCR & AI Extraction: Extract Shop Name, Challan Number, Product Details, Quantity, and Date using Google Vision API (or equivalent). Includes AI validation and duplicate detection. Shop-wise Segregation & Counter: Separate challans by customer/shop and automatically track count (e.g., 198 → 199 → 200). Automated Invoicing: Auto-generate PDF invoices (via PDFKit) at the 200-challan threshold and send them via automated email. Dashboard: Real-time view of uploaded, processed, and pending challans with shop-wise summaries. Tech Stack: Frontend: React.js Backend: Node.js (Express) Database: PostgreSQL OCR & PDF: Google Vision API, PDFKit