All of them. WebGL is supported by every major browser on every major operating system, with most having had support for more than a decade.

Browser Desktop Mobile Since
Chrome2011
Firefox2011
SafarimacOS 2011, iOS 2014
Edge2015
Opera2011
Samsung Internet2014

That covers something north of 99% of devices currently in use. If you can see the ball on the showcase landing page, you've already proved your browser supports WebGL.

WebGL 2 is the more recent revision — broader API surface, better performance for complex scenes. It reached universal modern-browser support when Safari shipped it in iOS 15 in late 2021, and remains the version most production code targets today.

WebGPU is the next generation — lower overhead, proper compute shaders, uses WGSL instead of GLSL. Browser support is good in Chrome and Edge, improving in Firefox and Safari. It's not yet a drop-in replacement for WebGL, but it's the direction the standard is heading.