Global Validation

Implement comprehensive input validation on both client and server sides, using allowlists over blocklists, sanitizing user input, and providing specific error messages to prevent security vulnerabilities. Use this skill when writing validation logic for forms, API endpoints, function parameters, or any user input. Use this skill when implementing server-side validation to ensure data integrity and security, adding client-side validation for immediate user feedback, or sanitizing input to prevent injection attacks. Use this skill when working with form components, API route handlers, data processing functions, or validation schemas. Use this skill when defining validation rules for data types, formats, ranges, required fields, or business logic constraints across all application entry points.