Web Development

Frontend

MDN Web Docs - developer.mozilla.org
The definitive web development documentation.

React Docs - react.dev
Official React documentation (excellent for learning).

CSS-Tricks - css-tricks.com
CSS tutorials, guides, and references.

Frontend Mentor - frontendmentor.io
Real-world frontend projects with designs.

Backend

Node.js Docs - nodejs.org/docs
Official Node.js documentation.

Express.js Guide - expressjs.com
Minimalist web framework documentation.