The Online Hotel Management System is a web-based application designed with React.js for the frontend and Firebase Firestore as the backend database. Utilizing React.js's component-based architecture, the system ensures a responsive and modular user interface, enhancing user experience through efficient state management and virtual DOM rendering. Firebase Firestore, as the backend database, offers real-time synchronization and scalable storage, enabling seamless data management for hotel-related information such as reservations, room availability, and staff management. This system streamlines various hotel operations, including reservation management, guest check-in/check-out processes, billing, and staff scheduling, all accessible through an intuitive and user-friendly interface. By automating processes and reducing manual effort, the system improves overall efficiency in hotel management, catering to both administrators and guests. Through the integration of React.js and Firebase Firestore, the Online Hotel Management System provides a modern and robust solution for hotel administrators to effectively manage their operations and enhance the guest experience. Keywords – Web application, frontend , database, web server.