BUILD. BATTLE.
BELONG.

Problems, UI battles, and real-time collaboration — all in one place.

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Everything in one place

One platform to practice,
compete, and collaborate.

Hundreds of LeetCode-style challenges with real test cases across Python, JavaScript, Java, and C++. Instant feedback, every submission.

Real-time collaborative editors. Code together with a shared cursor, live output, and chat.

Recreate a design with HTML & CSS and go head-to-head with other developers.

Drag, drop, and wire up architectures on an interactive canvas — then run a traffic simulation to see if your design holds up.

By the numbers

Coding problems

Submissions judged

Languages supported

Uptime, real-time sync

Join the playground where coders practice, battle, and build together — in real time.