This thesis describes the development of the "Car Rental" web application, designed to manage the car rental process. The application is developed using the Spring Boot framework, Java programming language, and MySQL database. The primary goal of the application is to enable users to easily search for and reserve vehicles, while administrators have access to advanced features for managing user accounts, vehicles, and reservations. The application includes the capability to generate PDF reports for users, who can download confirmation of their reservations. The user interface is developed using Thymeleaf for dynamic data presentation, and the application offers a secure authentication and authorization system. The paper thoroughly describes the application's architecture, the technologies used, and key functionalities, providing insights into development processes and implementation challenges.