[2] JSFiddle is an online IDE which is designed to allow users to edit and run HTML, JavaScript, and CSS code on a single page.

As of 2020, JSFiddle uses CodeMirror to support its editable fields, providing multicursors, syntax highlighting, syntax verification (linter), brace matching, auto indentation, autocompletion, code/text folding, Search and Replace to assist web developers in their actions.

[3] Code saved on JSFiddle may also be edited into new versions, shared with other parties, and forked into a new line.

JSFiddle is also widely used on Stack Overflow, the dominant question-answer online forum for the web industry.

In 2009, JSFiddle's predecessor, MooShell, was created by Piotr Zalewa as a website application which was exclusive to the MooTools community.