Worklet

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since April 2021.

Secure context: This feature is available only insecure contexts (HTTPS), in some or allsupporting browsers.

TheWorklet interface is a lightweight version ofWeb Workers and gives developers access to low-level parts of the rendering pipeline.

With Worklets, you can run JavaScript andWebAssembly code to do graphics rendering or audio processing where high performance is required.

Worklets allow static import ofECMAScript modules, if supported, usingimport.Dynamic import is disallowed by the specification — callingimport() will throw.

Worklet types

Worklets are restricted to specific use cases; they cannot be used for arbitrary computations like Web Workers. TheWorklet interface abstracts properties and methods common to all kind of worklets, and cannot be created directly. Instead, you can use one of the following classes:

Name	Description	Location	Specification
`AudioWorklet`	For audio processing with custom AudioNodes.	Web Audio render thread	Web Audio API
`AnimationWorklet`	For creating scroll-linked and other high performance procedural animations.	Compositor thread	CSS Animation Worklet API
`LayoutWorklet`	For defining the positioning and dimensions of custom elements.		CSS Layout API
`SharedStorageWorklet`	For running private operations on cross-site data, without risk of data leakage.	Main thread	Shared Storage API

Note:Paint worklets, defined by theCSS Painting API, don't subclassWorklet. They are accessed through a regularWorklet object obtained usingCSS.paintWorklet.

For 3D rendering withWebGL, you don't use worklets. Instead, you write vertex shaders and fragment shaders using GLSL code, and those shaders will then run on the graphics card.