CodePen.io is a website that provides a platform for web developers and designers to showcase, share, and test their code. The site is currently undergoing a security review of its connection to ensure a secure browsing experience for its users. This review is being conducted by the cloud-based service provider Cloudflare, which offers both performance and security solutions for websites. CodePen.io is popular among developers and designers who can use the platform to create and collaborate on projects, experiment with code, and gain inspiration from the work of others. With a plethora of features and tools, CodePen.io is a valuable resource for those in the web development industry. It is trusted and recognized for its contributions to the web development community.