In this thesis, we discuss the definition of a web application and its associated properties. In addition, we implement a web application of our own, and discuss its development process and functionality. The web application is implemented using modern technologies currently being used in the field. Specifically, the front-end of the application uses an HTML, CSS and JavaScript stack, with a Python backend, using the Flask framework and MongoDB (NoSQL) database for persistence. The web application is a School Administration system, much like a very simplified version of Neptun. The web application designed has three types of users: Administrators, Teachers and Students. Administrators can add students, remove or modify students and teachers on the platform, as well as add new subjects for students to register for. Teachers and administrators can send broadcast messages to the other users and also assign grades to the students. Students are able to register/de-register from subjects, and also view all their attained grades for all the completed subjects. In the thesis, we discuss exactly how the application data is stored in the database, and how it is retrieved and displayed for the user in a web browser.