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147: Charlotte Dann

Charlotte Dann is our guest for this episode! She joins Marie and Rachel to talk about her new project that got its start on CodePen: Hexatope – designing jewelry with hexagonal generative art.

Analyze CSS is now using Stylelint

In the CodePen editor, you can analyze your HTML, CSS, and JavaScript. HTML analysis is handled by HTML Inspector, so for example, if you type <il> instead of <li>, you’ll see a warning when analyzing your HTML: To some degree, JavaScript is linted as-you-type, so if you write some invalid JavaScript, you’ll be warned and […]

146: Content Inventory

Marie recently had the opportunity to do a content inventory on our documentation and document it. How meta! She’s joined by Chris to talk about why it’s important to do this from time to time and the benefit of having focused time to go deep into your content.

Regarding Referer Headers

There are certain URLs on CodePen that require something called a Referer header. From MDN: The Referer request header contains the address of the previous web page from which a link to the currently requested page was followed. The Referer header allows servers to identify where people are visiting them from and may use that […]

Improved Profile Organization

If you have an account on CodePen, you have a profile! If you’re logged in, you can even hit up this generic URL which redirects to it: Here’s mine, at You’re able to edit your profile, changing your user avatar, your links, bio, and all that. You can even link to CSS to […]

145: Preprocessors and Lambda

Tim H., Alex, and Marie are on to talk about preprocessors on CodePen — how they work, how we maintain them, what we do when a preprocessor becomes obsolete, and some thoughts on the future of preprocessors on CodePen.

#144: Integrating Braintree

We just brought back PayPal as a payment option, and we used Braintree to do it! Marie and Alex are on to talk about the how and why of adding a new payment provider to CodePen.

Fun with Mo.js

“Motion Graphics For The Web”, says mo · js. It’s a JavaScript library created by Oleg Solomka, otherwise known as LegoMushroom on Twitter and sol0mka here on CodePen. There is something about it that inspires really clean animation work and playful demos. After you check out these picks from the CodePen community, check out the […]

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