JSFiddle

Description

JSFiddle is a free, web-based code playground launched around 2010 that enables developers to write, run, and share HTML, CSS, and JavaScript (plus CoffeeScript) in a single interface. Its four-pane layout includes panels for code inputs and a live preview of results. Powered by CodeMirror, it offers syntax highlighting, autocompletion, linting, search/replace, and external resource support. Users can save unlimited “fiddles,” fork existing ones, collaborate in real-time, control versions, and embed snippets into blogs or docs. Widely used across developer communities like Stack Overflow, it's recognized as one of the most popular online IDEs.

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