Achieve mastery through challenge

Improve your skills by training with others on real code challenges

Sign Up

To join you must first prove your skills.
Choose your language to begin...

• Clojure
• C
• C++
• C#
• Crystal
• Dart
• Elixir
• F#
• Go
• Haskell
• Java
• JavaScript
• PHP
• Python
• Ruby
• Rust
• Shell
• SQL
• Swift
• TypeScript

Additional Languages:

*These languages are currently in beta. Once you enlist you will have an opportunity to train with them.

Sharpen your skills

Challenge yourself on kata, created by the
community to strengthen different skills.
Master your current language of choice,
or expand your understanding of a new one.

Train on kata

Solve the kata with your coding style
right in the browser and use test cases (TDD)
to check it as you progress. Retrain with new,
creative, and optimized approaches.

Earn ranks and honor

Kata are ranked to approximate difficulty.
As you complete higher ranked kata,
you progress through the ranks so we can
match you with relevant challenges.

Gain collaborative wisdom

Compare your solution with others
after each kata for greater understanding.
Discuss the kata, best practices, and
innovative techniques with the community.

Create your own kata

Author kata that focus on your interests and
train specific skillsets. Challenge the community
with your insight and code understanding.

Brought to you by

Accelerate your technical hiring.
Instant setup. Intuitive testing. Real results.

Identify top candidates with automated candidate testing.

Phone screen with collaborative coding interviews

Learn More