Fluid is a PHP template engine and is the de facto standard for any HTML-based output in the TYPO3 CMS ecosystem. However, it is not dependent on TYPO3 and can be used in any PHP project.

General documentation of Fluid can be found in the Documentation/ folder, see below link for a rendered version.

Repository

https://github.com/TYPO3/Fluid

Read online

https://docs.typo3.org/other/typo3fluid/fluid/main/en-us/

Packagist

https://packagist.org/packages/typo3fluid/fluid