Description: The logic of web applications refers to the structure and set of rules that determine how a web application operates and responds to user interactions. This logic is fundamental to the functioning of any online application, as it defines how requests are processed, how data is managed, and how results are presented to the user. Technically, the logic of web applications can be divided into three main layers: the presentation layer, which handles the user interface; the business layer, which contains processing logic and business rules; and the data layer, which manages interaction with databases and other storage systems. Proper implementation of this logic is crucial to ensure security, efficiency, and scalability of the application. Additionally, well-designed logic allows for a better user experience, as it facilitates navigation and interaction with the application. In the context of security testing, understanding the logic of a web application is essential to identify vulnerabilities and ensure that data and functionalities are protected against malicious attacks.