Houdini

Houdini was the abbreviated name of the CSS-TAG Houdini Task Force, which met from 2015 to 2019, and the name of the set of low-level CSS JavaScript APIs and proposed specifications that arose from that task force, some of which have been implemented.

The goal of the Houdini Task Force was to provide developers with the ability to create new CSS features without having to wait for web standards specifications to define them and browsers to implement them. This was achieved by proposing features to extend CSS by hooking into the styling and layout process of a browser's rendering engine. Houdini proposals gave developers access to the CSS Object Model (CSSOM), enabling developers to write code the browser can parse as CSS.

One main premise of Houdini features is to provide better performance than the equivalent JavaScript features by getting browsers to create the CSSOM directly, including layout, paint, and composite processes.

Houdini APIs include the CSS Painting API, the CSS Properties and Values API, the CSS Typed Object Model API, and Worklets.