An online code editor, learning environment, and community for front-end web development using HTML, CSS and JavaScript code snippets, projects, and web applications.

We're all for progressive enhancement, but CodePen is a bit unique in that it's all about writing and showing front end code, including JavaScript. It's required to use most of the features of CodePen.

CodePen is an online community for testing and showcasing user-created HTML, CSS and JavaScript code snippets. It functions as an online code editor and open-source learning environment, where …

CodePen is a social development environment for front-end designers and developers. Build and deploy a website, show off your work, build test cases to learn and debug, and find inspiration.

People use CodePen for all sorts of things: prototyping new ideas, reduced test cases for bugs, sending clients things to look at, evaluating potential hires, to finding inspiration. People also use CodePen as …

2 days ago · CodePen Blog This is where we post announcements, tips and tricks, new and updated features, fun roundups, new podcast episodes, and more. There's an RSS feed.

The Big Idea You write code in the editors, the results of that code are shown to you in the preview area. It’s simple, but powerful! Beginners and experts alike work best when they can see the results of …

Mar 6, 2012 · CodePen.IO (@CodePen) - Posts - Build, test, and discover front-end code 💻 Support: codepen.io/support | X (formerly Twitter)

Nov 1, 2021 · CodePen is a popular online code editor used by many developers around the world. It is also one of the recommended editors you can use for the freeCodeCamp curriculum. CodePen is …

Jan 16, 2026 · Codepen Codepen is an online code editor that provides a sandbox environment for testing and sharing HTML, CSS, and JavaScript code. It has separate panels for HTML, CSS, and …