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- "That Tech Show Podcast - EPISODE 33 - CODEPEN, CSS TRICKS AND OTHER NERDERY WITH CHRIS COYIER". 2021-09-28.
- CodePen "About page", Codepen.io, 17 March 2016.
- Silva, Patrícia (10 July 2020). "What is CodePen, and how to use it?". imaginarycloud.com. Archived from the original on 2020-08-12. Retrieved 5 January 2022.
- Kelly Kearsley (14 September 2015). "#50startups Update: How CodePen Raised $1 Million (in Five Minutes)". Startupbend. Archived from the original on 11 July 2018. Retrieved 17 March 2017.
- "codepen.io Traffic Statistics". SimilarWeb. Retrieved 2019-11-16.