ShaderLab is the WebGL2 GLSL Editor for the browser. Code your shaders right in your browser with a live view to progress in the background. Then share and garner feedback through comments and check out other creators.
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Said about ShaderLab as an alternative
Shaderlab is the only solution that allows using external images from imgur (or any website that allows for cross-domain access) as input textures, and allows the user to use his own MP3 files as audio inputs. It also have a Vim mode by pressing F9 on the editor, to use search and replace with regexp.