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CodePen vs RunJS: catalog facts
CodePen	RunJS
Freemium Free to use, with paid plans for additional features.	Free Free to download; no signup required according to the site.
Web	Windows, macOS, Linux
Live preview of HTML, CSS and JavaScript as you type Nothing to install	Live evaluation as you type, no project setup Node.js and browser environments in one app
Needs an internet connection Suited to small demos rather than full projects	JavaScript and TypeScript-style scratch work only, not a full editor Source code is not published
Web application	Downloadable app
Closed source	Closed source
License not stated	License not stated
Not stated if an account is needed	No account needed
Needs internet	Not stated if it works offline
Official website Full listing and sources Checked September 24, 2026	Official website Full listing and sources Checked October 1, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.