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 defining how custom CSS properties are being rendered, accessible 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.


The Worklet interface does not define any properties.


Adds the script module at the given URL to the current worklet.


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

Browser compatibilityUpdate compatibility data on GitHub

Chrome Edge Firefox Internet Explorer Opera Safari
Basic support 65 No Yes No 52 No
addModule 65 No 63 No 52 No
Android webview Chrome for Android Edge Mobile Firefox for Android Opera for Android iOS Safari Samsung Internet
Basic support 65 65 No Yes 52 No Yes
addModule 65 65 No 63 52 No Yes

See also

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