10.1 Input Validation and Sanitization

All user input must be validated and sanitized before processing or storage. We never trust data from users, regardless of whether it comes from authenticated users or public forms. This principle applies to all data sources, including form submissions, URL parameters, and API requests.

WordPress provides comprehensive sanitization functions that we use consistently throughout our themes and plugins. These functions are designed to handle common input types while preventing security vulnerabilities.

Laravel’s form request validation provides excellent tools for both validation and authorization. We create dedicated form request classes that handle all input validation in a centralized, testable way.