Sites
Reference sites worth bookmarking. Each one solves a specific problem.
MDN Web Docs
The canonical reference for HTML, CSS, JavaScript, and Web APIs. If you’re going to memorize one URL, make it this one.
javascript.info
Modern JavaScript tutorial with clear explanations and runnable examples. Covers the language from basics to advanced topics. Great for filling knowledge gaps.
patterns.dev
Design patterns and component patterns for modern web development. Covers rendering patterns (SSR, SSG, ISR), React patterns, and performance patterns with visual explanations.
Big-O Cheat Sheet
Time and space complexity reference for common data structures and algorithms. Print it out, tape it to your wall.
Can I Use
Browser support tables for HTML, CSS, and JavaScript features. Check before using a newer API in production.
TypeScript Playground
Write, share, and debug TypeScript in the browser. Useful for testing type-level code, sharing minimal reproductions, and exploring compiler options.
regex101
Regex testing with real-time explanation, match highlighting, and a quick reference. Supports JS, Python, Go, and more. Never write a regex blind again.
Bundlephobia
Check the size cost of adding an npm package. Shows minified size, gzipped size, download time, and composition. Use it before adding a dependency.