JSFiddle - Code Playground.

JSFiddle lets you “Test your JavaScript, CSS, HTML or CoffeeScript online with JSFiddle.” It includes code panel options to “Change code languages, preprocessors and plugins” for HTML, JavaScript and CSS, with options such as HTML, HAML, JavaScript, CoffeeScript, Babel + JSX, TypeScript, Vue, React, Preact, SCSS, SASS, PostCSS and Tailwind CSS.

Resources include “CDNJS” — “Type a library name to fetch from CDNJS” — and “URL - add directly into the HTML panel as a SCRIPT or LINK.” JSFiddle also provides “Simulating async requests” for JSON, JSONP, HTML and XML.

You can “Share or embed fiddle,” and “Customize the embeddable experience for websites,” with tabs for JavaScript, HTML, CSS and Result, light or dark visual themes, and an embed snippet. Editor settings let you “Customize the behavior and feel of the editor,” including auto-run code, auto-save code, live code validation, hot reload CSS, hot reload HTML, line numbers, wrap lines, code autocomplete and console in the editor.

JSFiddle includes “AI Code Completion.” “AI Code Completion is a BYOK implementation.” “The model we use is Codestral by Mistral.” “We won't save your API Key in our database, it's only stored in the browser for your convinience.”

The changelog notes: “Editor switch from CodeMirror to Monaco (same as VSCode),” “Collaboration is working again,” “Curated list of monospace coder fonts,” and “CSS Flexbox generator as a JSFiddle app.” The source material does not indicate a self-hosted version; it primarily describes the JSFiddle website/SaaS experience.