CodePen
FreeSocial front-end playground: write HTML, CSS and JavaScript in the browser with live preview, preprocessors and frameworks, then share pens and explore millions of community demos. Free accounts cover public work.
Why we recommend CodePen
CodePen is where front-end techniques get invented in public. The editor itself is unremarkable on purpose — three panes and a live preview — but the network effect is unmatched: search any CSS trick, animation pattern or component idea and someone has already built a forkable demo. For interviews, bug reproductions and teaching, a pen URL communicates more than paragraphs of description.
Best use cases
Best for: reproducing a CSS or JavaScript bug to share in an issue report, building interview take-homes and demos, teaching web fundamentals with instantly editable examples, and maintaining a public portfolio of UI experiments that doubles as a résumé for front-end roles.
Honest limitations
It is a scratchpad, not a project environment — no file system, real routing or backend beyond mocked requests on free accounts. Private pens and asset hosting require paid plans. Performance-heavy demos can lag inside the preview iframe compared to a standalone page.
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