MDN Web Docs is Mozilla's documentation platform for web technologies. It covers HTML, CSS, JavaScript, Web APIs, HTTP, and related standards in depth. For any question about how a specific HTML element, CSS property, or JavaScript method works, MDN is the most reliable and comprehensive reference available.
Beyond reference documentation, MDN includes learning guides that walk through web development concepts from the ground up. These guides are well-written and technically accurate, making them a solid resource for learning alongside more interactive platforms. The browser compatibility tables on each page are particularly useful for understanding which features are safe to use in production.
For working developers, MDN is the reference you keep open while coding. When you need to know the exact syntax for a CSS grid property, the parameters for a JavaScript array method, or which browsers support a specific Web API, MDN provides accurate, up-to-date information with examples.
For learners, the MDN guides provide a solid foundation in web fundamentals. The HTML and CSS guides in particular are thorough and well-structured. Reading MDN alongside a more interactive platform like freeCodeCamp or The Odin Project reinforces understanding of why things work the way they do, not just how to use them.
Completely free. MDN is maintained by Mozilla and community contributors. All documentation and guides are available at no cost.