269 interactive lessons in 11 programming languages. Read a short explanation, write the code in a real editor, and get your solution graded on the spot.
No long lectures, no videos you watch and forget. Just four steps that repeat in every lesson until they become a habit.
Every lesson opens with a short, focused explanation: one idea, real-world examples instead of textbook ones, then a clear task with a clear finish line.
You type in a professional editor with highlighting and shortcuts for every language, and your draft saves itself. No copy and paste: understanding comes from writing it yourself.
Press “Run and check” and your code runs right away. The automatic checks tell you what passed and what didn't, each one by name.
Step-by-step hints are there when you get stuck, and you move to the next lesson when you pass. Your streak, badges and progress are all saved.
The curriculum has 1406 carefully written checks that test what your code does, not how it looks. Every model solution passes its lesson's checks and every lesson's starter code fails them, so when your solution passes, your code really works.
Web, Python, SQL, Lua and Ruby run right in your browser. Nothing to install or configure.
Your C++, C# and Java programs are compiled and run on an isolated server with their real compilers.
Every lesson has three step-by-step hints. The model solution comes at the end, not the start.
A three-stage exam measures your level with no hints. Pass it and you get a certificate of mastery in your name.
There are 30 tracks, and each one is a short, complete course where every lesson builds on the last.
Start with your very first HTML tag and finish with a complete interactive app.
Go deeper into the box model, custom properties, positioning, container queries and more, so you understand what's really going on behind the styles you see.
Learn to scale headings, choose the right units, and set line length and text direction, because text is what people read most in any interface.
Work with data, functions and operations that take time, and build up to an interface that creates its elements from data.
A UI is built from data, so here you learn to filter, sort and group that data without touching the DOM directly.
Learn page layout, form validation, motion and accessibility: the things that make an interface comfortable to use in real life, not just nice to look at.
We grouped the tracks into three proven paths for the most popular goals. Start with the first track, and each one leads you into the next.
Start with your first HTML tag and finish with complete interactive interfaces you build yourself.
Learn Python to clean and summarize data, and SQL to pull exactly what you need from a database.
Build game logic in Lua and in the browser, then move on to C++ and C#, the languages of Unreal and Unity.
Short answers to the questions we hear most. The quickest way to get to know the platform is to try the first lesson.
Yes. Every track, every lesson and all the automatic grading are completely free, with no subscription and no ads.
No. Editing, running and grading all happen in the browser, and C++, C# and Java are compiled on an isolated server with no setup on your end.
Each lesson has prewritten checks that run your code and test how it behaves: they call your functions, click your page's buttons and read what your program prints. After every run you see the result of each check by name.
Start with the Web Basics or Python Basics track. Both start from absolute zero, and the first lesson takes ten minutes at most.
No. Your progress is saved in your browser automatically. An account is optional, and handy if you want your progress to follow you across devices.
Each language has an exam that unlocks once you finish its lessons. It has three stages, easy, medium and hard, with no hints and no model solution. At the end it tells you your level.
Pass all three stages of a language exam and a certificate of mastery in your name appears in your dashboard, ready to print or save as a PDF. If you're signed in, you can also issue a verified copy with an ID, a QR code and a verification page, once Wun Code re-grades your answers on the server, outside your browser. The completion certificate needs a verified copy of every exam.
Start the first lesson now, free and with no sign-up. After that, 58.5 hours of content is waiting for you.