ShaderTool is described as 'Provides a flexible and editable node-powered pipeline that allows you to write shaders without also having to have written an engine. Use the integrated code editor to directly write shader code in either HLSL (DirectX) or GLSL (OpenGL)' and is a Code Editor in the development category. There are more than 10 alternatives to ShaderTool for a variety of platforms, including Web-based, Windows, Linux, iPhone and Self-Hosted apps. The best ShaderTool alternative is Bitspace, which is both free and Open Source. Other great apps like ShaderTool are Alma.sh, SHADERed, Shadertoy and Shader Editor.