--- title: 418: CodeMirror 6 | daily.dev description: Chris Coyier and Stephen Shaw discuss CodePen's migration from CodeMirror 5 to CodeMirror 6, covering architectural changes, accessibility and performance... canonical: https://daily.dev/posts/418-codemirror-6-0im5qudyc twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: 418: CodeMirror 6 | daily.dev og:description: Chris Coyier and Stephen Shaw discuss CodePen's migration from CodeMirror 5 to CodeMirror 6, covering architectural changes, accessibility and performance... og:url: https://daily.dev/posts/418-codemirror-6-0im5qudyc og:image: https://api.daily.dev/og/posts/0Im5qUdYc.png og:image:alt: 418: CodeMirror 6 og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # 418: CodeMirror 6 **[CodePen](https://daily.dev/sources/codepen)** · 1 min read · 0 upvotes · 0 comments ## Summary Chris Coyier and Stephen Shaw discuss CodePen's migration from CodeMirror 5 to CodeMirror 6, covering architectural changes, accessibility and performance improvements, new theming options, and integration with modern JavaScript frameworks like Next.js. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [CodePen 2.0](https://daily.dev/posts/codepen-2-0-j2meaiqv9) · Hacker News · 3 upvotes · 0 comments - [426: Browserslist in CodePen 2.0](https://daily.dev/posts/426-browserslist-in-codepen-2-0-nyhuxfmn8) · CodePen · 0 upvotes · 0 comments - [JavaScript Weekly Issue 773: February 17, 2026](https://daily.dev/posts/javascript-weekly-issue-773-february-17-2026-xqchpt8vl) · JavaScript Weekly · 2 upvotes · 0 comments --- Tags: [#javascript](https://daily.dev/tags/javascript), [#nextjs](https://daily.dev/tags/nextjs), [#accessibility](https://daily.dev/tags/accessibility) [View this post on daily.dev](https://daily.dev/posts/418-codemirror-6-0im5qudyc) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"418: CodeMirror 6","url":"https://daily.dev/posts/418-codemirror-6-0im5qudyc","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/418-codemirror-6-0im5qudyc"},"datePublished":"2026-02-21T20:52:39.540Z","dateModified":"2026-02-21T20:52:56.332Z","description":"Chris Coyier and Stephen Shaw discuss CodePen's migration from CodeMirror 5 to CodeMirror 6, covering architectural changes, accessibility and performance...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/7cf484ceeae6bc7fc2161eddc603cd15?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/7cf484ceeae6bc7fc2161eddc603cd15?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"CodePen","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"CodePen","logo":"https://media.daily.dev/image/upload/t_logo,f_auto/v1/logos/codepen","url":"https://daily.dev/sources/codepen"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/418-codemirror-6-0im5qudyc","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"javascript,nextjs,accessibility","timeRequired":"PT1M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"CodePen","item":"https://daily.dev/sources/codepen"},{"@type":"ListItem","position":3,"name":"418: CodeMirror 6"}]} ```