AI-powered · 1,200+ challenges · Free to start

Master JavaScript.
One quest at a time.

From your first const to building React from scratch. Interactive lessons, real coding challenges, AI tutoring, and gamified streaks that actually make it stick.

50k+
learners
1,200+
challenges
200+
lessons
4.9★
rating
closures.quest.jsLive
01// Day 23 · Closures Quest 🔒
02function createCounter() {
03 let count = 0;
04 return () => ++count;
05}
06
07const next = createCounter();
08next(); // +10 XP 🔥
1
+10 XP·🔥 23 day streak
// features

Everything you need to actually ship code.

Tutorials don't make engineers. Reps do. We built every system around getting you to write code, today.

AI Tutor

Stuck on closures? Ask anything. Get beginner + advanced explanations, real-world analogies, and runnable code.

In-browser editor

Monaco-powered playground with auto-complete, error highlighting, and instant console output.

Gamified XP

Streaks, levels, coins and badges. Compete on weekly leaderboards. Learning that feels like a game.

Structured roadmap

Beginner → Intermediate → Advanced. Variables to building your own React. Nothing skipped.

1,200+ challenges

From easy loops to polyfills and event-loop puzzles. Hidden test cases. Instant feedback.

Visual explanations

Animated diagrams for execution context, the event loop, prototype chains, and the call stack.

Real projects

Calculator, weather app, expense tracker, kanban board, full ecommerce. Ship a portfolio.

Interview ready

100+ JS interview questions, machine coding rounds, timed MCQs, and mock interviews.

// the path

Zero to JavaScript engineer.

Three tracks, 201 lessons, 18 weeks. Every concept paired with reps.

014 weeks · 42 lessons

Beginner

  • Variables & types
  • Operators & conditions
  • Loops & functions
  • Arrays & objects
  • Scope basics
▸ Start here — free forever
026 weeks · 68 lessons

Intermediate

  • Closures & hoisting
  • Event loop & promises
  • Async / await
  • DOM & browser APIs
  • Build: Weather app
038 weeks · 91 lessons

Advanced

  • Prototypes & OOP
  • Currying, memo, debounce
  • Build your own React
  • System design
  • Interview rounds
// gamification

Learning that's actually addictive.

Streaks. XP. Coins. Badges. Leaderboards. Every lesson rewards your brain — so showing up tomorrow feels easier than skipping.

23
Day streak
14
Level
4,820
XP
WEEKLY LEADERBOARD
Top learners
Live
#1sarah.dev
12,480 XP
#2_arjun
11,220 XP
#3youYOU
9,870 XP
#4mei.codes
8,410 XP
#5noor
7,790 XP
🎯
Array Master
🥷
Closure Ninja
Promise Expert
🔥
Streak God
// ready?

Your JavaScript journey starts with one line.

Free forever for the beginner track. Upgrade anytime to unlock projects, AI tutor unlimited, and interview prep.

No credit card · 50,000+ learners · Made by developers, for developers