I recently completed a project called SmartTantra, a smart shopping system that combines IoT hardware with a MERN stack application. The idea was to simulate a cashier-less shopping experience where products are tagged with RFID cards and automatically added to a user's cart when scanned. Tech Stack: • React + Vite • Node.js + Express • MongoDB + Mongoose • JWT Authentication • Razorpay Payment Gateway • Arduino Uno + MFRC522 RFID Reader Features: ✅ RFID-based product scanning ✅ Real-time cart synchronization ✅ QR-based store entry ✅ Session management ✅ Razorpay payment integration ✅ Digital receipts ✅ Order history tracking ✅ Automatic stock updates after successful purchases Some challenges I faced: Handling duplicate RFID scans Serial communication between Arduino and Node.js CORS and authentication issues after deployment React Router refresh issues on Vercel Payment verification and receipt generation One thing I enjoyed most was connecting physical hardware to a full-stack web application and…