Twig is a PHP template engine and compiled rendering library designed to separate business logic from presentation. It functions as a secure template language that generates HTML output by combining dynamic data with reusable layouts.
The system emphasizes security through a focus on preventing cross-site scripting attacks via automatic output escaping and content sanitization. To ensure execution efficiency, it compiles templates into optimized PHP code and utilizes a caching mechanism to bypass parsing on subsequent requests.
The engine provides comprehensive tools for template composition, including block-based inheritance and modular UI development. It includes capabilities for data transformation through filters, template control logic for conditional branching and loops, and helper functions for dynamic content generation.