This thesis presents the development and evaluation of an Online Task Management Application, designed to facilitate efficient task management and collaboration among users. The application employs modern web technologies, including the MERN Stack, Zustand, JSON Web Tokens (JWT), and other supplementary tools such as Axios, Mongoose, and Material-UI. The project encompasses both back-end and front-end development, with the former focusing on setting up an Express server, directory structure, MongoDB models, services, controllers, middleware, and routes. The front-end development emphasizes the implementation of React components, actions, and the Zustand store for state management. The result is a comprehensive task management platform featuring user registration, login, group management, and task management functionalities. The thesis concludes with an exploration and evaluation of the application, discussing its effectiveness and user experience. Recommendations for potential future enhancements and improvements are also provided.