Twig

Twig is a modern templating language for PHP. It was created by Fabien Potencier and released in 2009, and it is developed as part of the Symfony ecosystem. Twig emphasizes readability, security, and performance, compiling templates to optimized PHP code and using caching to speed up rendering while keeping presentation and logic separate.

Twig syntax uses three delimiters: {{ expression }} for output, {% statement %} for control structures, and {# comments #} for notes within templates. The engine supports template inheritance through extends and blocks, as well as includes and embeds for composing templates. It offers a rich set of features, including filters, tests, functions, and macros, and it allows developers to create custom extensions to add new capabilities.

A key design principle of Twig is security. It provides automatic escaping by default for HTML output to help prevent cross-site scripting, with configurable options to disable escaping when needed. The templating language is extensible, enabling the creation of custom filters, tests, and functions, and it supports sandbox mode for restricted execution in untrusted environments.

Twig is released as open-source software under a BSD-style license and is maintained independently of PHP itself. It is widely used across PHP frameworks and projects, most notably as the default templating engine in Symfony, and is also employed in other systems such as Drupal 8 and later. It can be used as a standalone library or integrated into larger web applications through framework adapters.