This Online Code Runner is a browser-based development tool that allows users to write, edit, and execute HTML, CSS, and JavaScript code in a live environment. It is designed for developers, students, and beginners who want to quickly test front-end code without setting up a local development environment. Users can instantly preview output changes, experiment with layouts, debug styling issues, and validate JavaScript logic in real time. Such tools are especially useful for learning web development fundamentals, prototyping UI components, and sharing runnable code snippets during collaboration. If you are exploring automation, deployment workflows, or AI-powered development utilities, you may also find our guide on AI tools for project deployment helpful for moving projects from testing to production. For a deeper understanding of how browsers interpret and execute front-end code, refer to official resources from MDN Web Docs and performance best practices documented on web.dev .