From their homepage, “DevDocs combines multiple API documentations in a fast, organized, and searchable interface” and has become my most-used personal development resource. Up to date with the latest versions of each library, this is a must-have in your development toolkit.
MDN Web Docs
Peek under the ‘Technologies’ menu item to see all the different platforms it supports. Whereas DevDocs is a comprehensive API library reference, MDN Web Docs is a favorite due to examples, explanations and more thorough information for beginners.