Learn frontend byactually writing code
Written lessons with a live playground in every one. Earn XP, hold a streak and climb the board as you go.
Free to read · Sign in to save your progress
// Keep the published lessons, then total them up
const published = lessons.filter((l) => l. published);
const minutes = published.reduce(
(sum, l) => sum + l. minutes,
0
);
console.log("Total:", minutes);Console
Total: 50
Written, not filmed
Read at your own pace, search the text, copy the code. No 40-minute video to scrub through when you need one answer.
A playground in every lesson
Every concept ships with real code you can edit inline and run immediately. Break it, fix it, understand it.
Progress that sticks
XP, streaks and badges follow you across devices, so you always know where you left off and what to do next.
How the scoring works
Everything you do here is worth something. XP is the single currency behind your rank, your badges and your position on the leaderboard — there is no separate points system to keep track of.
- 01
Read a lesson
Work through the writing at your own pace and break things in the playground until the idea sticks.
+50 XP
- 02
Pass the quiz
Four questions at the end check you actually took it in. Full marks pays double.
+25–50 XP
- 03
Finish the course
Complete every lesson and a certificate is issued to you automatically.
+200 XP
- 04
Climb the board
All that XP sets your rank and your position against everyone else learning here.
8 ranks
Reasons to come back tomorrow
Learning alone is the main reason people quit. These are the parts that make it feel like something is happening.
See where you stand
Weekly, monthly and all-time boards, plus one for each track. Weekly resets mean starting today is not a disadvantage.
- 1Anish L0
- ?YouYour spot is open
Eight ranks to climb
From Newcomer to Master. Each one needs more than the last, so the title still means something at the top.
Show up, keep the flame
One lesson a day keeps it alive and pays a daily bonus. Miss a day and a freeze covers you — life happens.
12 to collect
Milestones worth noticing — a flawless quiz, a full week, a finished track. Locked ones always show how close you are.
- First StepsFinish your first lesson.
- Perfect RecallScore full marks on a quiz.
- Full WeekLearn seven days running.
- CertifiedEarn your first certificate.
A new problem every week
Solve it in the browser against a real test suite.
Week 32 · live now
Build your own groupBy
+150 XP
Start the course
One path from your first line of code to how the runtime actually works. Every lesson builds on the one before it, and finishing it end to end issues the certificate automatically.
JavaScript Masterclass
Beginner to advancedStart with no programming experience at all and finish understanding how JavaScript actually runs. What the internet is, what a browser does, how to write your first program — then scope, prototypes and promises, and finally the event loop, rendering performance and the browser security model.
- Foundations · 16 lessons
- Depth · 6 lessons
- Mastery · 6 lessons
More courses in progress
Written to the same standard: real code, a playground in every lesson, and no filler.
- React
- TypeScript
- CSS & Layout
Then prove it
The lessons are free and stay free. When you want something an employer can check, there is one exam: a single timed paper drawn fresh for you, marked against a fixed pass mark, and a certificate with a public link if you pass.
- Questions drawn per candidate, so no two papers match
- Answers save as you go — the clock runs on our server, not your laptop
- A topic-by-topic breakdown whether you pass or not
One exam, one price
JavaScript Certification
- Questions
- 65
- Sitting
- 2½ hours
- Pass mark
- 70%
Drawn across every part of the course — Foundations, Depth, Mastery, so passing means the whole syllabus rather than the third of it you liked most.
From the blog
Longer pieces that do not fit inside a lesson — how learning actually works, and the details worth getting right.
The frontend portfolio that actually gets replies
Most junior portfolios are three clones of the same todo app. Here is what hiring managers look for instead, and how to build it in a few weekends.
8 min== versus ===, settled properly
The rule everyone repeats is "always use triple equals". That is good advice and a bad explanation. Here is what each one actually does.
7 minWhy tutorials don't stick, and what to do instead
You can follow along with a four-hour video and still be unable to write the code yourself. Here is what is actually going wrong, and the small change that fixes it.
6 min
The first lesson takes 9 minutes
Pass its quiz and you are on the board with your first badge. Free to read without an account; signing in is what keeps the XP.
Start with How the Internet Works