Worklet - Web APIs

This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The Worklet interface is a lightweight version of Web Workers and gives developers access to low-level parts of the rendering pipeline. With Worklets, you can run JavaScript and WebAssembly code to do graphics rendering or audio processing where high performance is required.

Worklet types

Worklets are restricted to specific use cases; they cannot be used for arbitrary computations like Web Workers. The Worklet 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
`PaintWorklet`	For programmatically generating an image where a CSS property expects a file. Access this interface through `CSS.paintWorklet`.	Chrome: Main thread Gecko: Paint thread	CSS Painting API
`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

For 3D rendering with WebGL, 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.

Properties

The Worklet interface does not define any properties.

Methods

Worklet.addModule(): Adds the script module at the given URL to the current worklet.

Specifications

Specification	Status	Comment
Worklets Level 1 The definition of 'Worklet' in that specification.	Working Draft

Browser compatibility

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`Worklet` Experimental	Chrome Full support 65	Edge Full support 79	Firefox No support No Notes Disabled No support No Notes Disabled Notes Available only in Firefox Nightly. Disabled This feature is behind the `dom.worklet.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config.	IE No support No	Opera Full support 52	Safari No support No	WebView Android Full support 65	Chrome Android Full support 65	Firefox Android No support No Notes Disabled No support No Notes Disabled Notes Available only in Firefox Nightly. Disabled This feature is behind the `dom.worklet.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config.	Opera Android Full support 47	Safari iOS No support No	Samsung Internet Android Full support 9.0
`addModule` Experimental	Chrome Full support 65	Edge Full support 79	Firefox No support No Notes Disabled No support No Notes Disabled Notes Available only in Firefox Nightly. Disabled This feature is behind the `dom.worklet.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config.	IE No support No	Opera Full support 52	Safari No support No	WebView Android Full support 65	Chrome Android Full support 65	Firefox Android No support No Notes Disabled No support No Notes Disabled Notes Available only in Firefox Nightly. Disabled This feature is behind the `dom.worklet.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config.	Opera Android Full support 47	Safari iOS No support No	Samsung Internet Android Full support 9.0

Legend

Full support: Full support
No support: No support
Experimental. Expect behavior to change in the future.: Experimental. Expect behavior to change in the future.
See implementation notes.: See implementation notes.
User must explicitly enable this feature.: User must explicitly enable this feature.