What are Canvas and WebGL?

Canvas is an HTML feature for drawing images, shapes, and text from scripts. WebGL uses the GPU to render fast 2D and 3D graphics on a Canvas.

How NetKarte checks them

Check Canvas and WebGL separately in NetKarte's Graphics & GPU card. Even if a GPU name is unavailable in the same card, read WebGL's own availability as a separate result.

NetKarte creates separate temporary Canvas elements for 2D and WebGL and checks whether each context can be obtained. It tries webgl first, then experimental-webgl if no context is obtained, including when the first attempt throws an exception. It does not hash drawing output, create an identifier, or save the result.

What can it tell you?

“Available” means the page could obtain the relevant context. Browser settings, hardware, drivers, or security policy can all make WebGL unavailable.

Common misconceptions

Canvas or WebGL availability does not itself mean fingerprinting is occurring. A site could use rendering output with other signals for identification, but NetKarte only reports availability and creates no fingerprint ID.

Reading “Not available” and “Unavailable”

The same canvas cannot switch from a 2D context to WebGL, but NetKarte checks them on separate elements, so successful 2D creation does not prevent WebGL creation. It also continues the WebGL check if obtaining the 2D context throws an exception.

“Not available” means no context was returned; “Unavailable” means an exception prevented the check from establishing a result. If the WebGL retry obtains a context, the result is “Available.” These results alone do not establish a lack of browser support or a broken GPU. Even when WebGL is available, GPU names cannot be retrieved if the extension that exposes them is unavailable.

For 3D problems, also inspect the affected service's error and the browser's graphics information. NetKarte does not identify people from canvas availability or rendering output.