Results on every test case
See which inputs passed, which failed, and how long each one took. A failed submission tells you where to look, not just that you were wrong.
Free · animated · judged for real
Learn to code by watching it move.
Short animated lessons, a map that shows exactly what comes next, and problems checked by a real judge. Pick a language and start in two minutes.
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Stacks: matching bracketsstep 3/5
([{}]
([{
Push every opener. When a closer comes, the top of the stack must match it.
Your learning map
36 lessons in 15 tracks. Finish a stop, unlock the next.
Everything you need to actually improve
Most practice sites tell you that you failed. CodexBash shows you which case broke, how slow it was, and what to study next. That works whether you are three weeks into a course or ten years into a career.
Isolated, consistent runs
Every submission runs in its own locked-down container with fixed time and memory limits, so your result depends on your code and nothing else.
Progress you can act on
Topic-level accuracy, solve streaks and time trends show which areas are genuinely weak instead of leaving you to guess.
Guided learning paths
Structured courses take you from the idea to the implementation, with practice problems built into each lesson.
A catalog that builds on itself
Problems are grouped by topic and ordered so each one builds on what you already solved.
Where the problems are
Every topic in the catalogue, with how many problems sit under it today. The catalogue grows, and this counts it rather than describing it.
Free to learn. Pro if you would rather not see ads.
Every problem, every lesson and the judge are free with an account, and stay free. No card, no trial clock.
Free
₹0for good
Every problem, every lesson and the judge, with ads.
- Every problem in the catalogue
- The whole Learn track, with animations
- C, C++, Java and Python
- Results on every test case, with runtime and memory
- Submission history, streaks and leaderboards
Most popular
Pro
₹299per month
Everything in Free, without the ads, and a little more.
- Everything in Free
- No ads, anywhere on the site
- A weekly report on your progress, by email
- Daily practice reminders, by email
Start with one problem today
Free, with no card and no clock running. Students and working engineers welcome.