← Graphics & Compute
OffscreenCanvas
Probing…OffscreenCanvas is a web platform capability in the Graphics & Compute category. Render canvases from workers, off the main thread. Supported in Chromium 69+, Firefox 105+, and Safari 16.4+.
Try it
Loading demo…
Code
const off = canvas.transferControlToOffscreen()
const worker = new Worker(url)
worker.postMessage({ canvas: off }, [off])
// inside the worker:
self.onmessage = (e) => {
const ctx = e.data.canvas.getContext('2d')
function loop() {
ctx.fillRect(0, 0, w, h)
// ...draw bouncing shapes...
requestAnimationFrame(loop)
}
loop()
}Browser support
Chromium
69
Firefox
105
Safari
16.4
Frequently asked questions
Which browsers support OffscreenCanvas?
Supported in Chromium 69+, Firefox 105+, and Safari 16.4+.
Does OffscreenCanvas require HTTPS?
No. OffscreenCanvas works without a secure context, though serving your site over HTTPS is always recommended.
What is OffscreenCanvas used for?
Render canvases from workers, off the main thread.
Can I try OffscreenCanvas in my browser?
Yes. shwcs.net runs a live OffscreenCanvas demo that probes your current browser and lets you try the API. Everything runs locally — nothing is sent anywhere.