Twig is a modern template engine for PHP. Twig compiles templates down to plain optimized PHP code. The overhead compared to regular PHP code was reduced to the very minimum. Twig has a sandbox mode to evaluate untrusted template code. This allows Twig to be used as a template language for applications where users may modify the template design. Twig is powered by a flexible lexer and parser. This allows the developer to define its own custom tags and filters, and create its own DSL.