Free · 16 courses · AZ-900 prep

Code your future,
one small step at a time.

Bite-sized lessons with a real compiler beside every example, a VS Code-style playground, challenges that check your work, and full AZ-900 exam prep. All free, all in your browser.

Start learning free Open the playground

336lessons
1,411runnable examples
1,403practice questions
41challenges

Run

1name = input("What's your name? ")2age = int(input("How old are you? "))3print(f"Hi {name}! In 5 years you'll be {age + 5}.")

Input

Asha21

Output

What's your name? AshaHow old are you? 21Hi Asha! In 5 years you'll be 26.

1const n = prompt("Numbers?").split(" ").map(Number);2const sum = n.reduce((a, b) => a + b, 0);3console.log(`Sum ${sum}, average ${sum / n.length}`);

Input

4 8 15 16 23 42

Output

Numbers? 4 8 15 16 23 42Sum 108, average 18

1#include <iostream>2using namespace std;3 4int main() {5    int a, b;6    cin >> a >> b;7    cout << a << " + " << b << " = " << a + b;8}

Input

7 35

Output

7 + 35 = 42

+20 XP · lesson complete

16 languages and tools, one place to learn them

CSS

PHP

SQL

XML

Everything in one place

From your first `print()` to your first certification

Learn, run, practise and prove it, without installing a thing.

Lessons

A compiler beside every example

Short lessons that explain one idea at a time, with code you can run, edit and break right where you read it.

Python, JavaScript, Java, C, C++, SQL, PHP, React and more
Run it in the page: no install, no setup
A quiz at the end of every lesson

Browse the courses

Python · Lists 4 min

A list keeps values in order. Loop over it with for, and Python hands you each item in turn:

python Run

for x in [1, 2, 3]:
    print(x * x)

149

Playground

A VS Code-style editor in your browser

Write whole programs in 13 languages with files, tabs, formatting and a live preview for web pages.

Files save as you type, and sync to your account
Keyboard input, HTML preview and an AI helper
Share a link to your code

Open the playground

EXPLORERmain.pyapp.jsindex.htmlquery.sql

main.pyapp.js

def squares(n):    return [x * x for x in range(1, n + 1)] name = input("Name? ")print(f"Hello, {name}!")print("Squares:", squares(5))

INPUTAsha

OUTPUTName? AshaHello, Asha!Squares: [1, 4, 9, 16, 25]

Practice

Challenges that check your work

41 coding challenges from warm-ups to the tricky ones, each tested against hidden cases the moment you run it.

Easy, medium and hard, in six languages
Hints and a worked solution when you're stuck
XP for every one you solve

Start practising

FizzBuzzEasy · +30 XP

Test 1input 3 → Fizz

Test 2input 5 → Buzz

Test 3input 15 → FizzBuzz

Test 4input 7 → 7

All 4 tests passed

Certification

AZ-900, from first lesson to pass

Every skill in Microsoft's July 2026 outline, a pathway to exam day, 5 full-length mock tests and a quiz builder over 455 original questions.

Mock tests scored out of 1000, with a full review
Weak-spots quizzes built from your own mistakes
Diagrams for every big idea

See the certification

860/ 1000

Mock test 3 · Pass

Cloud concepts

Architecture and services

Management and governance

Mock tests 4 and 5

Progress

Watch yourself get better

XP for every lesson, quiz and challenge, a daily streak, levels and badges for the milestones, saved in your browser and your account.

Levels from Newcomer to Legend
71 badges to earn
Sign in once, carry it to any device

See the badges

Level 7 · Architect

2,340 / 2,800 XP

12 day streak

What we teach

16 courses and a certification, across five areas

Pick a language to start with; every course goes from the very first step to the advanced topics.

Web development5 courses

CSS

Programming5 courses

Data & analysis4 courses

SQL

NumPy

Pandas

Excel

Frameworks & formats2 courses

XML

Django

Cloud & certification1 course

AZ-900

Browse all courses Certifications

How it works

Three steps, every lesson

Read a short lesson
One idea at a time, in about five minutes, with an example right where you need it.
Run it, change it, break it
Every example has Run and Edit in the page, so you learn by trying, not just reading.
Prove it
Quizzes, challenges checked by hidden tests, XP, streaks and badges keep you going.

Meet the crew