Server-side validation is a critical security and data integrity measure performed on the web server after a user submits data from a client, such as a web browser. Its primary purpose is to ensure that all incoming data adheres to defined business rules, constraints, and security protocols before it is processed, stored in a database, or used in further application logic. Unlike client-side validation, which can be easily bypassed or disabled, server-side validation provides an uncompromisable layer of defense, making it essential for secure applications. When data arrives at the server, various checks are performed, including data type verification, format matching, uniqueness constraints, and complex business logic rules. If the data passes all these checks, it is deemed valid and the application proceeds; otherwise, the server sends an appropriate error message back to the client, prompting the user for corrections. This method safeguards against corrupt or malicious data entry and is the ultimate authority for data correctness, even when client-side validation is also in place for immediate user feedback. More details: https://t.me/s/lifeinfohubde