Smart Attendance System Using Dynamic QR Code

Abstract

Traditional paper-based and biometric attendance systems suffer from inefficiencies such as proxy attendance, time c onsumption, and data management difficulties. This paper presents a Smart Attendance System that leverages Dynamic QR Code generation with automatic token expiry and Google OAuth 2.0 single sign-on (SSO) authentication to mark student attendance in real time. The system is built on the MERN stack (MongoDB, Express.js, React.js, Node.js) and uses JSON Web Tokens (JWT) for session management. Faculty members generate time-limited QR codes for each class session; students scan these codes via their mobile browsers after authenticating through their institutional Google accounts. The system prevents proxy attendance through device-based and token-based validation. Attendance records are stored in a cloudbased database (MySQL/MongoDB) and made available to faculty as downloadable CSV/PDF reports. Evaluation results demonstrate an attendance marking accuracy of 98.6% and an average QR scan-to-record latency of under 1.2 seconds. The proposed system significantly reduces administrative overhead and eliminates manual errors