Why is Post and validation important in Laravel applications, and what problem does it solve for developers?

Why is Post and validation important in Laravel applications, and what problem does it solve for developers? The key reason to understand POST and validation is that Laravel applications are usually composed of several layers that must work together predictably. Tests can submit form data and assert validation errors or successful persistence. Ignoring that boundary can lead to duplicated logic, poor security, unnecessary database work, or code that is difficult to test. Why it matters in practice: Feature tests exercise application behavior through realistic HTTP requests, authentication, validation, routes and database interactions. The specific focus here is POST and validation: Tests can submit form data and assert validation errors or successful persistence. This question is designed to test not only terminology, but also how the concept fits into Laravel's request, application, database, security, or deployment workflow.